Common web browsers: chrome: 39, 47 firefox: 34, 38 IE: 11 (who the hell uses Tor with IE) Opera: 26, 12.17 iOS app (who uses Tor with the iOS web browser)
Common OS: win: 7, 8.1 mac: 10.10 linux: ubuntu (no stats concerning specific versions of linux nor ubuntu available in the shitty pie chart)