comScore has released its search data for December 2011, and Google continues to dominate in terms of share, with 65.9%, compared with 65.4% in November 2011 and 66.6% in December 2010. Year-over-year, queries increased 9.7% in December.

Yahoo queries came in with 14.5% share, compared with 15.1% in November 2011 and 16.0% in December 2010. Microsoft’s Bing’s share of searches in December was 15.1%, compared with 15% in November 2011 and 12.0% in December 2010. Since Bing powers Yahoo search, combined the two search engine’s share of searches was 29.6%, compared with 30.1% in November 2011. AOL queries declined 8% in December with 1.6% share.

In terms of search queries, this was the first month Bing overtook Yahoo in terms of search queries, says Citi analyst Mark Mahaney. Both search portals are powered by the same technologies but clearly Yahoo search traffic is declining, which is just another problem added to new CEO’s Scott Thompson’s list of problems for the company.

As Mahaney writes in his report citing the new data, “Scott Thompson has his work cut out for him.”