Google has retained its status as the top search engine in the US, logging more than half of all search queries last month.

Research firm comScore recorded 7.6 billion search queries in May, 3.9 billion of which were made from Google, giving the search engine a 50.7 per cent market share. 

The figure is a one per cent increase from April, when Google claimed a 49.7 market share, and an increase of more than three per cent since the start of 2007.

Google was also the only search engine among the top five to gain market share last month.

Yahoo saw its market share drop from 26.8 to 26.4 per cent. The firm has seen its share of the search market fall by more than two per cent since the beginning of the year. 

Time Warner's search services, which include former net giant AOL, dropped from five per cent to 4.6 per cent in May. All other search engines combined accounted for three per cent of all queries. 

Of the top five search engines only Microsoft's saw its share of the market remain constant, logging 782 million queries last month and giving the company 10.3 per cent of the US market. 

Overall, Americans are searching more than they did a year ago. The 7.6 billion queries in May represent an 11 per cent increase on 2006.