The only show the current versions of Firefox and Chrome on the Top Versions. The other category drops as soon as Firefox and Chrome gain which means that past versions of all browsers (eg, Chrome 31, 30, etc) are grouped into other. The "Top Families" show all versions together of each browser, and you may notice that the other category on that page is very minimal.
http://clicky.com/marketshare/global/web-browsers/