Google continued its dominance of the U.S. search marketplace in September, with its sites accounting for 64.9% of the search market share, according to ComScore.

The digital measuring company reported that Google's search market share was up from the 64.6% recorded in August.

Microsoft, which launched its Bing search engine in June, also recorded a slight gain, moving to a 9.4% search market share from 9.3% in August. Yahoo kept a solid hold on its second place ranking with an 18.8% share of the market, down half a percentage point from its 19.3% market share in August.

Of the 13.8 billion searches Americans conducted in September, ComScore said that Google accounted for 9 billion of them. Yahoo users made 2.6 billion searches, followed by Microsoft users, who conducted 1.3 billion searches. About 541 million searches were conducted on the Ask Network while AOL users made 416 million searches, according to ComScore.

Although still far back in the rankings, Facebook recorded the most growth in searches, as its 384 million searches represented a gain of 19%.

Searches on Amazon sites dropped 12% to 191 million, and eBay was down 4% to 621 million. MySpace sites were searched 494 million times in September, representing a 12% drop from September. Even so, MySpace maintained a significant lead over Facebook, its main social networking rival.

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