Thank you all.
CDarwin was correct in his observation:
"I think the topic poster just wants an idea as to how many chances for mutation would have passed along the road to humanity, which is a really problematic question because it's impossible to demark the start of that 'road' in any way not completely arbitrary."
I understand that it my question was asking for a "completely arbitrary" figure, but nevertheless this discourse has helped my understanding.
Furthermore, I want to applaud all of you on this forum. It is one of the only places on the internet that are accesible, inteligent, argumentative, non-adhominen, and polite. Thank you for that.