Nielsen has published its US search statistics for July, revealing an impressive 51% year-over-year increase for Microsoft's sites (MSN/Windows Live/Bing), which held 13.6% of the market. Yahoo, which is now powered by Bing behind the curtain, represented a 14.3% share last month, falling 17% from a year prior. Despite the contrasting performance on-year, both companies witnessed a similar sequential increase of 4% and 2% respectively.

Google, of course, maintained its position as the top search provider with 64.2% of the market, falling 1% from the month and year-ago periods. placed fourth in Nielsen's stats at 2.1% of the market, while AOL claimed 1.9%, shrinking 38% from last year.

Market share aside, search volume has decreased by 16% from 10.5 billion in July 2009 to 8.8 billion in July 2010. MSN/Windows Live/Bing was the only one of the top three engines to experience a boost, with searches climbing 28% from 0.9 billion to 1.2 billion.