The problem is that those numbers just aren’t right. There’s something like 9% of the human genome that hasn’t been sequenced; all we can say about that in comparison with the chimpanzee genome is that the latter has similar stretches of similar, highly repetitive DNA. For the part that has been sequenced and has also been sequenced and assembled in the chimpanzee genome, the best current estimates are that ~1.5% of the human genome consists of short stretches of DNA that isn’t present in the chimpanzee genome, ~3% (with a large uncertainty) represents large stretches of DNA that has been duplicated in one genome but not the other. In the remaining DNA, which the part that’s similar and lines up nicely, 1.2% of individual bases are different.