Google accounted for 65.26% of all US searches for the four weeks ended April 28, while Yahoo, MSN Search and Ask.com received 20.73%, 8.46% and 3.69%, respectively, according to Hitwise, MarketingCharts reports.

Among the top four search engines, Google was the only one to increase its share of searches - up some 11% - from a year earlier, when it accounted for 58.64% of US searches.

The remaining 47 search engines in the Hitwise Search Engine Analysis Tool accounted for 1.86 percent of US searches, Hitwise said.

Search engines remain the primary way web users navigate to key industry categories, Hitwise said. Nearly 45% of traffic to Health and Medical sites came from search engines, for example. (MarketingCharts has more data.)