ClassicLunatic.com - USTC Supply Snapshots

Date / Time	Circulating Supply	Difference	Total Supply	Difference	Comm. Pool	USD per coin	Block
Jul 17, 2023, 05:38	9,796,839,587		9,796,839,587		4,932,942	$0.018240	13,691,155
Jul 17, 2023, 05:37	9,796,839,587	-2	9,796,839,587	-2	4,932,942	$0.018188	13,691,145
Jul 17, 2023, 05:36	9,796,839,589	-1	9,796,839,589	-1	4,932,936	$0.018200	13,691,135
Jul 17, 2023, 05:35	9,796,839,590		9,796,839,590		4,932,929	$0.018206	13,691,124
Jul 17, 2023, 05:34	9,796,839,590		9,796,839,590		4,932,928	$0.018350	13,691,114
Jul 17, 2023, 05:33	9,796,839,590		9,796,839,590		4,932,925	$0.018389	13,691,104
Jul 17, 2023, 05:32	9,796,839,590	-1	9,796,839,590	-1	4,932,923	$0.018460	13,691,094
Jul 17, 2023, 05:31	9,796,839,591	-800	9,796,839,591	-800	4,932,922	$0.018439	13,691,083
Jul 17, 2023, 05:30	9,796,840,391	-4	9,796,840,391	-4	4,932,720	$0.018426	13,691,073
Jul 17, 2023, 05:29	9,796,840,395	-1	9,796,840,395	-1	4,932,717	$0.018508	13,691,063
Jul 17, 2023, 05:28	9,796,840,396		9,796,840,396		4,932,716	$0.018550	13,691,053
Jul 17, 2023, 05:27	9,796,840,396		9,796,840,396		4,932,715	$0.018513	13,691,043
Jul 17, 2023, 05:26	9,796,840,396	-65	9,796,840,396	-65	4,932,711	$0.018516	13,691,032
Jul 17, 2023, 05:25	9,796,840,461	-2	9,796,840,461	-2	4,932,695	$0.018482	13,691,022
Jul 17, 2023, 05:24	9,796,840,463		9,796,840,463		4,932,694	$0.018490	13,691,012
Jul 17, 2023, 05:23	9,796,840,463		9,796,840,463		4,932,679	$0.018494	13,691,002
Jul 17, 2023, 05:22	9,796,840,463	-1	9,796,840,463	-1	4,932,679	$0.018569	13,690,992
Jul 17, 2023, 05:21	9,796,840,464		9,796,840,464		4,932,676	$0.018480	13,690,981
Jul 17, 2023, 05:20	9,796,840,464		9,796,840,464		4,932,670	$0.018587	13,690,971
Jul 17, 2023, 05:19	9,796,840,464		9,796,840,464		4,932,663	$0.018461	13,690,961
Jul 17, 2023, 05:18	9,796,840,464	-4	9,796,840,464	-4	4,932,653	$0.018504	13,690,951
Jul 17, 2023, 05:17	9,796,840,468		9,796,840,468		4,932,651	$0.018344	13,690,941
Jul 17, 2023, 05:16	9,796,840,468		9,796,840,468		4,932,651	$0.018319	13,690,930
Jul 17, 2023, 05:15	9,796,840,468		9,796,840,468		4,932,645	$0.018409	13,690,920
Jul 17, 2023, 05:14	9,796,840,468		9,796,840,468		4,932,644	$0.018346	13,690,910
Jul 17, 2023, 05:13	9,796,840,468	-119	9,796,840,468	-119	4,932,639	$0.018237	13,690,900
Jul 17, 2023, 05:12	9,796,840,587	-120	9,796,840,587	-120	4,932,602	$0.018178	13,690,889
Jul 17, 2023, 05:11	9,796,840,707	-800	9,796,840,707	-800	4,932,571	$0.018183	13,690,879
Jul 17, 2023, 05:10	9,796,841,507		9,796,841,507		4,932,371	$0.018216	13,690,869
Jul 17, 2023, 05:09	9,796,841,507		9,796,841,507		4,932,371	$0.018222	13,690,859
Jul 17, 2023, 05:08	9,796,841,507		9,796,841,507		4,932,367	$0.018229	13,690,849
Jul 17, 2023, 05:07	9,796,841,507		9,796,841,507		4,932,367	$0.018211	13,690,838
Jul 17, 2023, 05:06	9,796,841,507		9,796,841,507		4,932,364	$0.018240	13,690,828
Jul 17, 2023, 05:05	9,796,841,507	-13	9,796,841,507	-13	4,932,362	$0.018276	13,690,818
Jul 17, 2023, 05:04	9,796,841,520		9,796,841,520		4,932,350	$0.018219	13,690,807
Jul 17, 2023, 05:03	9,796,841,520		9,796,841,520		4,932,350	$0.018250	13,690,797
Jul 17, 2023, 05:02	9,796,841,520	-5	9,796,841,520	-5	4,932,350	$0.018256	13,690,787
Jul 17, 2023, 05:01	9,796,841,525		9,796,841,525		4,932,349	$0.018185	13,690,777
Jul 17, 2023, 05:00	9,796,841,525	-1	9,796,841,525	-1	4,932,349	$0.018161	13,690,767
Jul 17, 2023, 04:59	9,796,841,526	-3,966	9,796,841,526	-3,966	4,932,348	$0.018184	13,690,757
Jul 17, 2023, 04:58	9,796,845,492	-3,980	9,796,845,492	-3,980	4,931,343	$0.018226	13,690,746
Jul 17, 2023, 04:57	9,796,849,472		9,796,849,472		4,930,343	$0.018183	13,690,736
Jul 17, 2023, 04:56	9,796,849,472		9,796,849,472		4,930,343	$0.018128	13,690,726
Jul 17, 2023, 04:55	9,796,849,472		9,796,849,472		4,930,343	$0.018146	13,690,716
Jul 17, 2023, 04:54	9,796,849,472		9,796,849,472		4,930,341	$0.018247	13,690,706
Jul 17, 2023, 04:53	9,796,849,472	-2	9,796,849,472	-2	4,930,339	$0.018226	13,690,696
Jul 17, 2023, 04:52	9,796,849,474	-17	9,796,849,474	-17	4,930,334	$0.018263	13,690,686
Jul 17, 2023, 04:51	9,796,849,491	-4	9,796,849,491	-4	4,930,326	$0.018183	13,690,676
Jul 17, 2023, 04:50	9,796,849,495	-4	9,796,849,495	-4	4,930,319	$0.018219	13,690,666
Jul 17, 2023, 04:49	9,796,849,499	-4	9,796,849,499	-4	4,930,315	$0.018124	13,690,655
Jul 17, 2023, 04:48	9,796,849,503		9,796,849,503		4,930,309	$0.018133	13,690,645
Jul 17, 2023, 04:47	9,796,849,503		9,796,849,503		4,930,301	$0.018040	13,690,635
Jul 17, 2023, 04:46	9,796,849,503	-24	9,796,849,503	-24	4,930,297	$0.018056	13,690,625
Jul 17, 2023, 04:45	9,796,849,527	-4	9,796,849,527		4,930,293	$0.017968	13,690,614
Jul 17, 2023, 04:44	9,796,849,531	-2	9,796,849,527	-6	4,930,284	$0.018020	13,690,604
Jul 17, 2023, 04:43	9,796,849,533		9,796,849,533		4,930,283	$0.018026	13,690,594
Jul 17, 2023, 04:42	9,796,849,533		9,796,849,533		4,930,280	$0.017984	13,690,584
Jul 17, 2023, 04:41	9,796,849,533	-1	9,796,849,533	-1	4,930,280	$0.017960	13,690,574
Jul 17, 2023, 04:40	9,796,849,534		9,796,849,534		4,930,279	$0.017961	13,690,564
Jul 17, 2023, 04:39	9,796,849,534		9,796,849,534		4,930,279	$0.017957	13,690,554
Jul 17, 2023, 04:38	9,796,849,534		9,796,849,534		4,930,279	$0.018002	13,690,543
Jul 17, 2023, 04:37	9,796,849,534	-1	9,796,849,534	-1	4,930,279	$0.018019	13,690,533
Jul 17, 2023, 04:36	9,796,849,535	-1	9,796,849,535	-1	4,930,270	$0.018002	13,690,523
Jul 17, 2023, 04:35	9,796,849,536		9,796,849,536		4,930,270	$0.018000	13,690,513
Jul 17, 2023, 04:34	9,796,849,536		9,796,849,536		4,930,268	$0.017910	13,690,502
Jul 17, 2023, 04:33	9,796,849,536	-34	9,796,849,536	-34	4,930,268	$0.018185	13,690,492
Jul 17, 2023, 04:32	9,796,849,570		9,796,849,570		4,930,256	$0.018256	13,690,482
Jul 17, 2023, 04:31	9,796,849,570	-34	9,796,849,570	-34	4,930,256	$0.018226	13,690,472
Jul 17, 2023, 04:30	9,796,849,604		9,796,849,604		4,930,246	$0.018292	13,690,462
Jul 17, 2023, 04:29	9,796,849,604	-1	9,796,849,604	-1	4,930,243	$0.018348	13,690,452
Jul 17, 2023, 04:28	9,796,849,605		9,796,849,605		4,930,242	$0.018352	13,690,441
Jul 17, 2023, 04:27	9,796,849,605		9,796,849,605		4,930,237	$0.018421	13,690,431
Jul 17, 2023, 04:26	9,796,849,605		9,796,849,605		4,930,218	$0.018418	13,690,421
Jul 17, 2023, 04:25	9,796,849,605	-99	9,796,849,605	-99	4,930,218	$0.018467	13,690,411
Jul 17, 2023, 04:24	9,796,849,704	-10	9,796,849,704	-10	4,930,193	$0.018500	13,690,401
Jul 17, 2023, 04:23	9,796,849,714		9,796,849,714		4,930,188	$0.018539	13,690,390
Jul 17, 2023, 04:22	9,796,849,714	-1	9,796,849,714	-1	4,930,187	$0.018539	13,690,380
Jul 17, 2023, 04:21	9,796,849,715	-1	9,796,849,715	-1	4,930,178	$0.018500	13,690,370
Jul 17, 2023, 04:20	9,796,849,716		9,796,849,716		4,930,171	$0.018569	13,690,360
Jul 17, 2023, 04:19	9,796,849,716	-1	9,796,849,716	-1	4,930,171	$0.018536	13,690,349
Jul 17, 2023, 04:18	9,796,849,717	-1	9,796,849,717	-1	4,930,160	$0.018530	13,690,339
Jul 17, 2023, 04:17	9,796,849,718		9,796,849,718		4,930,157	$0.018539	13,690,329
Jul 17, 2023, 04:16	9,796,849,718	-104	9,796,849,718	-104	4,930,157	$0.018516	13,690,319
Jul 17, 2023, 04:15	9,796,849,822	-1	9,796,849,822	-1	4,930,130	$0.018550	13,690,309
Jul 17, 2023, 04:14	9,796,849,823		9,796,849,823		4,930,119	$0.018545	13,690,298
Jul 17, 2023, 04:13	9,796,849,823		9,796,849,823		4,930,115	$0.018666	13,690,288
Jul 17, 2023, 04:12	9,796,849,823		9,796,849,823		4,930,115	$0.018671	13,690,278
Jul 17, 2023, 04:11	9,796,849,823		9,796,849,823		4,930,114	$0.018718	13,690,268
Jul 17, 2023, 04:10	9,796,849,823		9,796,849,823		4,930,112	$0.018680	13,690,257
Jul 17, 2023, 04:09	9,796,849,823		9,796,849,823		4,930,111	$0.018707	13,690,247
Jul 17, 2023, 04:08	9,796,849,823	-333	9,796,849,823	-333	4,930,107	$0.018624	13,690,237
Jul 17, 2023, 04:07	9,796,850,156	-117	9,796,850,156	-117	4,930,020	$0.018558	13,690,227
Jul 17, 2023, 04:06	9,796,850,273		9,796,850,273		4,929,988	$0.018577	13,690,217
Jul 17, 2023, 04:05	9,796,850,273		9,796,850,273		4,929,988	$0.018577	13,690,207
Jul 17, 2023, 04:04	9,796,850,273	-1	9,796,850,273	-1	4,929,983	$0.018530	13,690,197
Jul 17, 2023, 04:03	9,796,850,274	-4	9,796,850,274	-4	4,929,982	$0.018584	13,690,186
Jul 17, 2023, 04:02	9,796,850,278		9,796,850,278		4,929,975	$0.018560	13,690,176
Jul 17, 2023, 04:01	9,796,850,278	-831	9,796,850,278	-831	4,929,973	$0.018555	13,690,166
Jul 17, 2023, 04:00	9,796,851,109		9,796,851,109		4,929,762	$0.018532	13,690,156
Jul 17, 2023, 03:59	9,796,851,109	-32	9,796,851,109	-32	4,929,759	$0.018541	13,690,145

Date / Time

Circulating Supply

Difference

Total Supply

Difference

Comm. Pool

USD per coin

Block

Jul 17, 2023, 05:38

9,796,839,587

4,932,942

$0.018240

13,691,155

Jul 17, 2023, 05:37

9,796,839,587

-2

9,796,839,587

-2

4,932,942

$0.018188

13,691,145

Jul 17, 2023, 05:36

9,796,839,589

-1

9,796,839,589

-1

4,932,936

$0.018200

13,691,135

Jul 17, 2023, 05:35

9,796,839,590

4,932,929

$0.018206

13,691,124

Jul 17, 2023, 05:34

9,796,839,590

4,932,928

$0.018350

13,691,114

Jul 17, 2023, 05:33

9,796,839,590

4,932,925

$0.018389

13,691,104

Jul 17, 2023, 05:32

9,796,839,590

-1

9,796,839,590

-1

4,932,923

$0.018460

13,691,094

Jul 17, 2023, 05:31

9,796,839,591

-800

9,796,839,591

-800

4,932,922

$0.018439

13,691,083

Jul 17, 2023, 05:30

9,796,840,391

-4

9,796,840,391

-4

4,932,720

$0.018426

13,691,073

Jul 17, 2023, 05:29

9,796,840,395

-1

9,796,840,395

-1

4,932,717

$0.018508

13,691,063

Jul 17, 2023, 05:28

9,796,840,396

4,932,716

$0.018550

13,691,053

Jul 17, 2023, 05:27

9,796,840,396

4,932,715

$0.018513

13,691,043

Jul 17, 2023, 05:26

9,796,840,396

-65

9,796,840,396

-65

4,932,711

$0.018516

13,691,032

Jul 17, 2023, 05:25

9,796,840,461

-2

9,796,840,461

-2

4,932,695

$0.018482

13,691,022

Jul 17, 2023, 05:24

9,796,840,463

4,932,694

$0.018490

13,691,012

Jul 17, 2023, 05:23

9,796,840,463

4,932,679

$0.018494

13,691,002

Jul 17, 2023, 05:22

9,796,840,463

-1

9,796,840,463

-1

4,932,679

$0.018569

13,690,992

Jul 17, 2023, 05:21

9,796,840,464

4,932,676

$0.018480

13,690,981

Jul 17, 2023, 05:20

9,796,840,464

4,932,670

$0.018587

13,690,971

Jul 17, 2023, 05:19

9,796,840,464

4,932,663

$0.018461

13,690,961

Jul 17, 2023, 05:18

9,796,840,464

-4

9,796,840,464

-4

4,932,653

$0.018504

13,690,951

Jul 17, 2023, 05:17

9,796,840,468

4,932,651

$0.018344

13,690,941

Jul 17, 2023, 05:16

9,796,840,468

4,932,651

$0.018319

13,690,930

Jul 17, 2023, 05:15

9,796,840,468

4,932,645

$0.018409

13,690,920

Jul 17, 2023, 05:14

9,796,840,468

4,932,644

$0.018346

13,690,910

Jul 17, 2023, 05:13

9,796,840,468

-119

9,796,840,468

-119

4,932,639

$0.018237

13,690,900

Jul 17, 2023, 05:12

9,796,840,587

-120

9,796,840,587

-120

4,932,602

$0.018178

13,690,889

Jul 17, 2023, 05:11

9,796,840,707

-800

9,796,840,707

-800

4,932,571

$0.018183

13,690,879

Jul 17, 2023, 05:10

9,796,841,507

4,932,371

$0.018216

13,690,869

Jul 17, 2023, 05:09

9,796,841,507

4,932,371

$0.018222

13,690,859

Jul 17, 2023, 05:08

9,796,841,507

4,932,367

$0.018229

13,690,849

Jul 17, 2023, 05:07

9,796,841,507

4,932,367

$0.018211

13,690,838

Jul 17, 2023, 05:06

9,796,841,507

4,932,364

$0.018240

13,690,828

Jul 17, 2023, 05:05

9,796,841,507

-13

9,796,841,507

-13

4,932,362

$0.018276

13,690,818

Jul 17, 2023, 05:04

9,796,841,520

4,932,350

$0.018219

13,690,807

Jul 17, 2023, 05:03

9,796,841,520

4,932,350

$0.018250

13,690,797

Jul 17, 2023, 05:02

9,796,841,520

-5

9,796,841,520

-5

4,932,350

$0.018256

13,690,787

Jul 17, 2023, 05:01

9,796,841,525

4,932,349

$0.018185

13,690,777

Jul 17, 2023, 05:00

9,796,841,525

-1

9,796,841,525

-1

4,932,349

$0.018161

13,690,767

Jul 17, 2023, 04:59

9,796,841,526

-3,966

9,796,841,526

-3,966

4,932,348

$0.018184

13,690,757

Jul 17, 2023, 04:58

9,796,845,492

-3,980

9,796,845,492

-3,980

4,931,343

$0.018226

13,690,746

Jul 17, 2023, 04:57

9,796,849,472

4,930,343

$0.018183

13,690,736

Jul 17, 2023, 04:56

9,796,849,472

4,930,343

$0.018128

13,690,726

Jul 17, 2023, 04:55

9,796,849,472

4,930,343

$0.018146

13,690,716

Jul 17, 2023, 04:54

9,796,849,472

4,930,341

$0.018247

13,690,706

Jul 17, 2023, 04:53

9,796,849,472

-2

9,796,849,472

-2

4,930,339

$0.018226

13,690,696

Jul 17, 2023, 04:52

9,796,849,474

-17

9,796,849,474

-17

4,930,334

$0.018263

13,690,686

Jul 17, 2023, 04:51

9,796,849,491

-4

9,796,849,491

-4

4,930,326

$0.018183

13,690,676

Jul 17, 2023, 04:50

9,796,849,495

-4

9,796,849,495

-4

4,930,319

$0.018219

13,690,666

Jul 17, 2023, 04:49

9,796,849,499

-4

9,796,849,499

-4

4,930,315

$0.018124

13,690,655

Jul 17, 2023, 04:48

9,796,849,503

4,930,309

$0.018133

13,690,645

Jul 17, 2023, 04:47

9,796,849,503

4,930,301

$0.018040

13,690,635

Jul 17, 2023, 04:46

9,796,849,503

-24

9,796,849,503

-24

4,930,297

$0.018056

13,690,625

Jul 17, 2023, 04:45

9,796,849,527

-4

9,796,849,527

4,930,293

$0.017968

13,690,614

Jul 17, 2023, 04:44

9,796,849,531

-2

9,796,849,527

-6

4,930,284

$0.018020

13,690,604

Jul 17, 2023, 04:43

9,796,849,533

4,930,283

$0.018026

13,690,594

Jul 17, 2023, 04:42

9,796,849,533

4,930,280

$0.017984

13,690,584

Jul 17, 2023, 04:41

9,796,849,533

-1

9,796,849,533

-1

4,930,280

$0.017960

13,690,574

Jul 17, 2023, 04:40

9,796,849,534

4,930,279

$0.017961

13,690,564

Jul 17, 2023, 04:39

9,796,849,534

4,930,279

$0.017957

13,690,554

Jul 17, 2023, 04:38

9,796,849,534

4,930,279

$0.018002

13,690,543

Jul 17, 2023, 04:37

9,796,849,534

-1

9,796,849,534

-1

4,930,279

$0.018019

13,690,533

Jul 17, 2023, 04:36

9,796,849,535

-1

9,796,849,535

-1

4,930,270

$0.018002

13,690,523

Jul 17, 2023, 04:35

9,796,849,536

4,930,270

$0.018000

13,690,513

Jul 17, 2023, 04:34

9,796,849,536

4,930,268

$0.017910

13,690,502

Jul 17, 2023, 04:33

9,796,849,536

-34

9,796,849,536

-34

4,930,268

$0.018185

13,690,492

Jul 17, 2023, 04:32

9,796,849,570

4,930,256

$0.018256

13,690,482

Jul 17, 2023, 04:31

9,796,849,570

-34

9,796,849,570

-34

4,930,256

$0.018226

13,690,472

Jul 17, 2023, 04:30

9,796,849,604

4,930,246

$0.018292

13,690,462

Jul 17, 2023, 04:29

9,796,849,604

-1

9,796,849,604

-1

4,930,243

$0.018348

13,690,452

Jul 17, 2023, 04:28

9,796,849,605

4,930,242

$0.018352

13,690,441

Jul 17, 2023, 04:27

9,796,849,605

4,930,237

$0.018421

13,690,431

Jul 17, 2023, 04:26

9,796,849,605

4,930,218

$0.018418

13,690,421

Jul 17, 2023, 04:25

9,796,849,605

-99

9,796,849,605

-99

4,930,218

$0.018467

13,690,411

Jul 17, 2023, 04:24

9,796,849,704

-10

9,796,849,704

-10

4,930,193

$0.018500

13,690,401

Jul 17, 2023, 04:23

9,796,849,714

4,930,188

$0.018539

13,690,390

Jul 17, 2023, 04:22

9,796,849,714

-1

9,796,849,714

-1

4,930,187

$0.018539

13,690,380

Jul 17, 2023, 04:21

9,796,849,715

-1

9,796,849,715

-1

4,930,178

$0.018500

13,690,370

Jul 17, 2023, 04:20

9,796,849,716

4,930,171

$0.018569

13,690,360

Jul 17, 2023, 04:19

9,796,849,716

-1

9,796,849,716

-1

4,930,171

$0.018536

13,690,349

Jul 17, 2023, 04:18

9,796,849,717

-1

9,796,849,717

-1

4,930,160

$0.018530

13,690,339

Jul 17, 2023, 04:17

9,796,849,718

4,930,157

$0.018539

13,690,329

Jul 17, 2023, 04:16

9,796,849,718

-104

9,796,849,718

-104

4,930,157

$0.018516

13,690,319

Jul 17, 2023, 04:15

9,796,849,822

-1

9,796,849,822

-1

4,930,130

$0.018550

13,690,309

Jul 17, 2023, 04:14

9,796,849,823

4,930,119

$0.018545

13,690,298

Jul 17, 2023, 04:13

9,796,849,823

4,930,115

$0.018666

13,690,288

Jul 17, 2023, 04:12

9,796,849,823

4,930,115

$0.018671

13,690,278

Jul 17, 2023, 04:11

9,796,849,823

4,930,114

$0.018718

13,690,268

Jul 17, 2023, 04:10

9,796,849,823

4,930,112

$0.018680

13,690,257

Jul 17, 2023, 04:09

9,796,849,823

4,930,111

$0.018707

13,690,247

Jul 17, 2023, 04:08

9,796,849,823

-333

9,796,849,823

-333

4,930,107

$0.018624

13,690,237

Jul 17, 2023, 04:07

9,796,850,156

-117

9,796,850,156

-117

4,930,020

$0.018558

13,690,227

Jul 17, 2023, 04:06

9,796,850,273

4,929,988

$0.018577

13,690,217

Jul 17, 2023, 04:05

9,796,850,273

4,929,988

$0.018577

13,690,207

Jul 17, 2023, 04:04

9,796,850,273

-1

9,796,850,273

-1

4,929,983

$0.018530

13,690,197

Jul 17, 2023, 04:03

9,796,850,274

-4

9,796,850,274

-4

4,929,982

$0.018584

13,690,186

Jul 17, 2023, 04:02

9,796,850,278

4,929,975

$0.018560

13,690,176

Jul 17, 2023, 04:01

9,796,850,278

-831

9,796,850,278

-831

4,929,973

$0.018555

13,690,166

Jul 17, 2023, 04:00

9,796,851,109

4,929,762

$0.018532

13,690,156

Jul 17, 2023, 03:59

9,796,851,109

-32

9,796,851,109

-32

4,929,759

$0.018541

13,690,145

The difference cells relate to the supply cells to the left. The figure can be positive, negative or zero. The difference is calculated as the difference between the supply to the left of it at the given time snapshot and the supply column above it. In other words, how much the supply has gone up or down in that time period. On page 1, the top difference cell shows the difference during the currrent time period and the next to appear. This row is higlighted to show this is ongoing. Other columns show a snapshot of data taken at the given day and time in the far left column. All times shown are GMT (Greenwich Mean Time). To highlight rows just tap or click on the row(s) to cycle background colours.