I missed noting when it passed 10%, cause while I had heard there was a place you could find out, I hadn't bothered to find it yet. But now I have and of course that means I will keep track. And perhaps note it here when I pass certain milestones.
In any case, I started at my current company on 11 Jan 2006. It is now 31 Jul 2006. Just about six and a half months later.
At this point 12.09% of the employees of my company were hired after I was.