According to comScore, more than 750 million people 15 years old or older, or about 95 percent of the Internet audience around the world, performed 61 billion searches in August. That's an average of 80 searches per users, comScore said. Those 750 million people used Google for 37.1 billion searches. Of those, 31 billion searches were performed on Google, and 5 billion were at Google's video-sharing site YouTube.com, according to comScore.
Google Tops Charts in Global Search, Computerworld, October 11, 2007.