As of December 2008, the Internet has exceeded 1 billion visitors. Of those visitors, Asia-Pacific has the highest percent of users with 416.3 million users which equates to almost half of the total with 41.3%.
Breaking down these numbers even more, China had 179.7 million users in December 2008, with the US not far behind with a large 163.3 million.
With the Internet still growing daily, these numbers are sure to at least double- most likely seeing great increases in the near future.
Source: eMarketer, February 17 2009