Here are some numbers from our webmail service. These cover the dates 2011-08-03 - 2011-08-29 inclusive, during which time there were 1320906 logins by 23087 users. Edit: I have corrected & clarified the Mobile Safari breakdown.
users : platform 20130 Windows 7193 Mac OS 2671 iOS 1714 Linux (desktop) 1054 Android 393 BlackBerry 313 Symbian 92 Samsung 89 Kindle 69 SonyEricsson 57 Nokia 54 J2ME 36 SunOS 11 LG users : browser 12965 MS IE 12063 Firefox 7190 Chrome 5165 Safari (desktop) 4014 Safari (mobile) 446 other mobile 406 Opera 109 Opera Mini 9052 MS IE 8 5277 MS IE 7 2960 MS IE 9 1477 MS IE 6 12 MS IE 5 for Mac 6566 Firefox 5 6392 Firefox 3.6 4226 Firefox 6 1457 Firefox 4 823 Firefox 3.5 775 Firefox 3.0 322 Firefox 2 66 Firefox 7 48 Firefox 1 31 Firefox non-standard 6390 Chrome 13 4132 Chrome 12 176 Chrome 14 124 Chrome 11 112 Chrome 10 49 Chrome 8 42 Chrome 6 41 Chrome 9 32 Chrome 7 32 Chrome 5 28 Chrome 4 25 Chrome 15 4974 Safari 53x 194 Safari 52x 61 Safari 3xx 61 other desktop WebKit 14 Safari 4xx 3445 Mobile Safari 53x 554 Mobile Safari 52x 136 Mobile Safari 41x 40 Mobile Safari 42x 2466 iOS WebKit 53x 960 Android WebKit 53x 258 iOS WebKit 52x 257 other WebKit 52x 170 other WebKit 53x 55 Android WebKit 52x