From March 2009 to April 2009, Google gains .5% market share for search query volume ( Core Searches ), whereas both MSN and Yahoo lose search volume ( -.1% search market share for each company ). ASK.COM remained the same from March to April of 2009. AOL lost the largest piece of search market share from March to April at a rate of -.3%.
Google's search market share for the month of April is 64.2%.
Source: ComScore, searchenginewatch.com