What percentage of Internet keyboard users are hunt-and-peck typers?

Some people can type without needing to look at the keys. Other people need to look at the keys before pressing a key.

I'm curious if there is any published research on the percentage of users that need to hunt for the keys vs. the percentage that can type without looking at the keyboard.

I was able to find several studies comparing speeds - as expected, the people who typed without looking won - but could not find any on population percentages that use each method.