Google is reporting:
We launched Google Public DNS in December 2009 to help make the web faster for everyone. Today, we’re no longer an experimental service. We’re the largest public DNS service in the world, handling an average of more than 70 billion requests a day.
DNS acts like the phone book of the Internet. If you had to look up hundreds or thousands of phone numbers every day, you’d want a directory that was fast, secure and correct. That’s what Google Public DNS provides for tens of millions of people.
Google Public DNS has become particularly popular for our users internationally. Today, about 70 percent of its traffic comes from outside the U.S. We’ve maintained our strong presence in North America, South America and Europe, and beefed up our presence in Asia. We've also added entirely new access points to parts of the world where we previously didn't have Google Public DNS servers, including Australia, India, Japan and Nigeria.
Google Public DNS: 70 billion requests a day and counting