http://searchengineland.com/google-still-no-1-search-engine-on-earth-24853

pointing to
http://www.comscore.com/Press_Events/Press_Releases/2009/8/Global_Search_Market_Draws_More_than_100_Billion_Searches_per_Month

From the Market Overview study:
"....
Google Sites attracted significantly more searches than any other engine with 76.7 billion searches conducted, or 67.5 percent market share. Yahoo! Sites ranked second worldwide with 8.9 billion searches (7.8 percent share), followed closely by Chinese search engine Baidu with 8 billion searches (7.0 percent share).
...."