Any forensics people out there? How long does it take for a body to decompose and leave only bones?

There was an article in today’s newspaper that told of a hunter finding a “human remains” in a field up in the N. Georgia mountains. The way the article was written, it sounded like the dead person hadn’t been wrapped or covered up, he was just found lying there.

Assuming normal summer southern weather (mostly warm, fair amount of rain, no hurricanes), how long does it take for a body to be reduced to bones?

(Of course, the county police no doubt will do their lab work, but I’m just curious about what the time frame is)