According to the latest data from Experian Hitwise, Google was responsible for 64.42% of searches in the U.S. in March, 2011. Bing-powered search — which includes both search.yahoo.com and bing.com — accounted for 30% of U.S. searches. Last October, Google controlled 72.15% of the U.S. search market for September, 2010. Bing powered search accounted for 23.64%.

The fact that Bing has crossed the 30% mark in the U.S. is significant in and of itself. Looking back through Experian Hitwise’s archives underscores the tremendous amount of growth for Bing-powered search. The rate of growth appears to be increasing. Google still clearly leads Bing more than 2 to 1. But when you consider that that ratio was 3 to 1 last fall, the gap appears to be closing. Bing is growing by five or six percent each month, whereas Google is losing two to three percent.

If you do assume a constant trajectory, Bing will overtake Google in less than a year — January 2012, to be precise.

What isn’t hypothetical is that Bing has real momentum.

http://mashable.com/2011/04/11/bing-search-growth/