Talkback stats only show 10 days, and of course don't enumerate users
who haven't crashed...
*1.5.0.x total = 5,435 unique users
460 http://talkback-public.mozilla.org/reports/thunderbird/TB150/index.html
244 http://talkback-public.mozilla.org/reports/thunderbird/TB1502/index.html
457 http://talkback-public.mozilla.org/reports/thunderbird/TB1504/index.html
276 http://talkback-public.mozilla.org/reports/thunderbird/TB1505/index.html
380 http://talkback-public.mozilla.org/reports/thunderbird/TB1507/index.html
299 http://talkback-public.mozilla.org/reports/thunderbird/TB1508/index.html
*1.0.x total = 5,435 unique users
1741 http://talkback-public.mozilla.org/reports/thunderbird/TB10/index.html
1885 http://talkback-public.mozilla.org/reports/thunderbird/TB102/index.html
268 http://talkback-public.mozilla.org/reports/thunderbird/TB105/index.html
813 http://talkback-public.mozilla.org/reports/thunderbird/TB106/index.html
728 http://talkback-public.mozilla.org/reports/thunderbird/TB107/index.html
0 1.0.8
winxp and win2k constitute the vast majority of 1.0.x topcrash OS.
Oddly, except for 1.0.6 where it is Mac and almost on win topcrash.