I was just doing the final numbers for last month and I don't see a thread yet on the various search engines did, so here are my results:
(Site is a in English but world-wide audience, non-commerce info site)
October 2009: Google 82.90% Yahoo 7.16% MS 5.00% AOL 1.09%
Year-to-Date, 2009: Google 81.74% Yahoo 8.44% MS 4.67% AOL 1.11%
Full Year Numbers, 2008: Google 78.70% Yahoo 9.12% MS 5.40% AOL 1.30%
Notes: Google has been slightly rising over the year. Yahoo is the biggest recent loser, off roughly 2% from its high in July of this year. MS's latest offering Bing has fallen the last two months - but only 1/2 % total and it is still a full 1% above the lows of June/July. AOL is in its usual spot - just above 1%.