70 percent of mobile searchers click to call a business directly from Google's search results!

Google commissioned Ipsos, an independent market research company, to understand consumer attitudes about click to call.
The survey of 3,000 mobile searchers who recently made purchases in seven verticals (Travel, Restaurant, Auto, Local Services, Retail, Finance, Technology) revealed that 70 percent of mobile searchers click to call a business directly from Google's search results.
Google provides AdWords advertisers with several phone call metrics. If you want to add call extensions, you can learn more about it here.