While Google sits enthroned as the search engine giant in its market share, Yahoo and Bing are more effective in search results, yielding the highest success rates, according to a search-engine study.

Web tracking company Experian Hitwise released its study results, which indicated Google's dominance among search engines, accounting for 66.05 percent of all U.S. searchers in July, 2011. Yahoo! Search received 14.49 percent, followed by Bing with 13.19 percent.

"Success rate," defined as the click-through  rate after a user conducts a search, resulted higher in Yahoo and Bing. Yahoo, after farming out search to Bing in the 2009 deal, yielded a success rate of 81.36 percent, while Bing yielded 80.04 percent.

Google searches, however, resulted in 67.56 percent of actual visits to a website, after searches are made.

The results suggest that there is much room for Google to improve the search accuracy.

"The share of unsuccessful searches highlights the opportunity for both the search engines and marketers to evaluate the search engine result pages to ensure that searchers are finding relevant information," said Experian Hitwise in its press release.

Both Yahoo and Bing are powered by the Bing search engine, and are proven to be  more effective at providing users with precise results.

One explanation is Bing's "decision engine" model and the bells and whistles it has. However, Google also has many of those features, so they might not fully explain the discrepancy between the effectiveness differences.

Another possible explanation is demographics.A report from Chitika calculated that 72 percent of Bing traffic comes from Internet Explorer users. Bing is the default search engine of IE, which is the default Internet browser of the Windows OS.

In other words, many Bing users are simply Windows users who never bothered to change their default setting for their search engine.

Moreover, Bing indexes 114 (Internet average 100) for "no college" versus 97 percent for Google. Bing also indexes lower for teenagers, higher for African Americans, and higher for Hispanics compared to Google, according to estimates from Quantcast.

Google and Bing index roughly the same for gender and income.

Lastly, Google is much larger than Bing, accounting for 66.05 percent of all U.S. searches in July 2011 versus 14.49 percent for Yahoo and 13.19 percent for Bing.

According to the report, July was the third straight month for Bing-powered searches to continue rising.