I dont believe that percentage. Especially considering how spread the homo branch already was more than 100 000 years ago. And from which point do you start counting? Homo erectus?
You could go back to Lucy and add only a few million. Compared to the billions at this specific instant, it just doesn't make a difference.
Given that we only hit the first billion people in 1804 and the second billion in 1927 it's not all that shocking.
But this is also just the non-intuitiveness of exponential growth which has only now tapering off.