Google topped the US explicit core search market in January 2011 with 65.6% market share, according to a report from research firm comScore. Yahoo! came a distant second with 16.1% (up 0.1percentage points). Microsoft was third with 13.1% market share.

The report said Americans conducted 17 billion total core searches in January, with Google sites accounting for 65.6% of share, decrease from 66.6% in December 2010.

Yahoo! US’ total core search market decreased to 17.9% in January 2011 from 18.8% in December, while Microsoft sites grabbed 12.8% market share, up 0.8 percentage points versus December.

The study also said Ask Network got 3.1% of the US core search market, while AOL Network accounted for 1.6%, both registering a drop of 0.1 and 0.1 percentage points, respectively.

In January 2010, Google accounted for 11.1 billion search queries, followed by Yahoo! with 2.7 billion queries and Microsoft sites with 2.2 billion searches.

According to the report, AOL search network queries decreased by 5% to 296 million from 312 million in December.