This sounds about right, Yandex.ru and Rambler.ru are top 2. Google is way behind. Mail.ru uses Google's search results, but I don't think Google+Mail.ru come close to Rambler as simple math suggests. Many people also use 2-3 SEs as results sometimes vary a lot.
I think Google might be underrepresented in the statistics above. Pulled this from my logs for a 150 page site in Russian on a dot-com address - Jan 1-Jul 8 2005:
Yandex 3118 (Site ranks #2 for best single keyword) Google 1586 (Site ranks #5+6 for same keyword) Rambler 841 (Not in top 100 for same single keyword, but #4 for best phrase) Google Images 260 Yahoo 224 (Site ranks #9 for best single keyword) MSN 213 (Site ranks #4 for best single keyword) Altavista 35 (Site ranks #17 for best single keyword) Other SE:17 Total SE: 6294
This certainly confirms the strong standing of Yandex and Rambler, but indicates that Google's place is somewhere between them.
rencke, "referrers on 1 site" is not a good gauge to go by IMHO. Google may look a lot stronger because your site is optimized for it - which is why you are on WebmasterWorld in the first place ;) so your site is already "google-biased". Also, with Google you may have traffic spilled from other countries.
There's a lot more to identifying country traffic then a number of referrers or a site position for a specific keyword.
Plus your stats are for 6 month, I presume? That's a 1000/month - a bit small (no offence) to draw statistical conclusions.
Look at Alexa rankings (although I believe alexa penetration is pretty low in Russia, which just means that these sites should in fact rank higher): Yandex - #363 Rambler - #637
Mail.ru - #380 (but most people are there to check email, not to search)