Every month about this time comScore releases the search engine rankings data, and I try to remember report it here. These are not the actual search engine rankings that you see when you search at a search engine, which are constantly changing. Think of this more as the “market share” for the search engine industry.

comScore, Inc. (NASDAQ: SCOR), a leader in measuring the digital world, has released its monthly comScore qSearch analysis of the U.S. search marketplace.

Google, of course, remained at the top of the U.S. explicit core search market in December 2012 with 66.7 percent market share, followed by Microsoft with 16.3 percent (up 0.1 percentage points) and Yahoo! with 12.2 percent (up 0.1 percentage points). Ask Network accounted for 3 percent of explicit core searches, followed by AOL, Inc. with 1.8 percent (up 0.1 percentage points).