The BBC has a terrific page up — just put in your birthday and it tells you where you stand numerically. Check this out. It even tells you how it derived the estimates. Here's one member of our aNewDomain.net edit team — he just typed in his birthday and, voila. Just hit the BBC site here.
Here’s a cool site to hit. Put in your birthday and it’ll estimate where you fall inside the 7B human range. What number are you?