Average male adult hair count, NW1-7

[Dav7]

Just wondering if anybody could pinpoint a site/ article stating how many hairs a NW1/ NW2/ NW3/ NW3v/ NW4/ NW5/ NW6/ NW7 has. I've read somewhere something like 100,000 hairs for a NW1, would that be accurate?

Also at what point on the Norwood scale does it become impossible to ever revive a full look such as were you started at with NW1?