comScore released its monthly analysis of the U.S. search marketplace last week.

Google Sites led the “explicit core search" market (searches occuring directly/explicitly at those destinations) in May with a 65.9 percent share, followed by Yahoo! (15.9 percent), and Microsoft Sites (14.1 percent). Ask and AOL rounded out the list with 3 percent and 1.5 percent shares respectively.

According to comScore, more than 17.0 billion explicit core searches were conducted in May (up 5 percent versus April). Google Sites ranked first with 11.2 billion searches (up 5 percent), followed by Yahoo! Sites with 2.7 billion (up 5 percent), Microsoft Sites with 2.4 billion (up 4 percent), Ask Network with 502 million (up 2 percent) and AOL, Inc. with 254 million (up 2 percent).

When it comes to “core search” – which includes partner searches, cross-channel searches and contextual searches – Google once again let the way. Google Sites accounted for 63.3 percent of total core search queries conducted, followed by Yahoo! Sites with 19.6 percent (up 1.7 percentage points) and Microsoft Sites with 13.1 percent.

The Ask Network comprised 2.6 percent of total search queries, followed by AOL, Inc. with 1.3 percent.