Google maintained its dominance in search last month, capturing 66.3 percent of explicit core searches and 64.3 percent of total core searches, which includes Google Instant.

Yahoo and Microsoft's Bing trailed behind, with market share in the teens, though Bing did see a slightly uptick, according to data from comScore.

This is the second month that comScore has included the impact of Google Instant – which offers suggestions as someone types – when calculating its search engine rankings.

ComScore said last month that when people type something into Google, hit "enter," and then click on a link, it counts that activity in its "explicit core search" results. Results that show up in Google Instant as someone types will be included in "total core search" results if a user pauses on that for at least three seconds, comScore said.

As a result, Google had 66.3 percent of the explicit core search market in October, up very slightly from 66.1 percent the month before. Yahoo came in second with 16.5 percent of the market, down 0.2 percent, followed by Microsoft sites with 11.5 percent, a 0.3 percent increase.

Overall, more than 16.6 billion explicit core searches were conducted in October, with Google capturing 11 billion searches, followed by Yahoo with 2.7 billion, and Microsoft with 1.9 billion. Ask.com – which recently moved its focus away from core search – had 598 million searches, followed by AOL with 346 million.

On total core search, which includes Google Instant, Google was the only company in the top five to make any gains month-over-month. Google had 64.3 percent of the market, up 1.4 percent from the previous month. Yahoo had 18.5 percent, down 0.7 percent, followed by Microsoft at 12.1 percent, down 0.4 percent.

Web users in the U.S. conducted 18.4 billion total core search queries in October; 11.8 billion on Google, followed by Yahoo with 3.4 billion, and Microsoft with 2.2 billion.

Last month, Yahoo complained that including Google Instant in search market share reports was "misleading," but the company this week introduced its own Google Instant-esque product known as Yahoo Search Assist.