Google’s share of the U.S. desktop search market dipped from 67 percent to 65.4 percent from November to December of last year, according to comScore’s monthly qSearch analysis.

The 1.6 percentage points Google’s sites lost went directly to Yahoo, whose sites increased in share from 10.2 percent to 11.8 percent, according to comScore. The change can be attributed to December being the first month of Yahoo’s five-year partnership with Mozilla, in which Yahoo replaced Google as the default search engine on Firefox.

The other three companies comScore looked at – Microsoft, Ask Network, and AOL – had search shares of 19.7 percent, 2 percent, and 1.2 percent for December, respectively. While Ask Network stayed the same, AOL did lose 0.1 percentage point to Microsoft.

Earlier this month, StatCounter released its monthly report, which differed slightly from that of comScore because the two traffic analytics platforms measure differently. While StatCounter looks at “Bing,” comScore ranks “Microsoft sites,” which give the Seattle software company 7 more percentage points.