I stopped using Firefox last year, when I began using Chrome (through the development version Chromium) in September 2009. As it underwent rapid development versions on the Mac, I updated frequently and I began to taking periodic version snapshots until January of this year, shortly before Chrome went official for Mac.

2009-10-06 1:52pm

Chrome = 4.0.220.1
Chromium = 4.0.221.5 (27975)

2009-10-15 9:06pm

Chrome = 4.0.222.5
Chromium = 4.0.223.1 (29225)

2009-10-23 11:43am

Chrome = 4.0223.8
Chrome = 4.0223.11 (8:56pm)
Chromium = 4.0224.3 (29892)

2009-11-15 1:48pm

Chrome = 4.0.254.0
Chromium = 4.0.249.0 (32026)

2009-11-24 8:58pm

Chrome = 4.0.249.12
Chromium = 4.0.257.0 (32997)

2009-12-20 10:31pm

Chrome = 4.0.249.43
Chromium = 4.0.277.0 (35069)

2010-01-06 7:11pm

Chrome = 4.0.249.49
Chromium = 4.0.288.0 (35431)

2010-01-14 8:29pm

Chrome = 4.0.249.49 (35163)
Chromium = 4.0.299.0 (36242)

2010-01-24 10:37pm

Chrome = 4.0.249.49 (35163)
Chromium = 4.0.306.0 (36978)

2010-11-28 1:18pm

Chrome = 7.0.517.44
Chromium = 6.0.443.0 (50319)