Google Inc. and Yahoo Inc. have increased their shares in the U.S. Internet search market, a survey said on Monday.

Google has increased its share of the market to 47.4 percent with a gain of 0.4 percent during December, while No.2-ranked Yahoo's share rose 0.3 percent to 28.5 percent in the same period, Internet audience measurement firm comScore Networks said.

The data also show that No.3-ranked Microsoft's share slid 0.5 percent to 10.5 percent while IAC/InterActive Corp's Ask.com's share dipped 0.1 percent to 5.4 percent.

An estimated 6.7 billion searches were conducted by U.S. Internet users in December, up one percent from November. Of them, 3.2 billion searches were performed on Google sites, while Yahoo drew 1.9 billion searches.

The number of U.S. Internet search queries has grown 30 percent since December of 2005, comScore said.

Editor: Yan