That logic doesn't make any sense unless you assume there are 100 men to every woman on earth, or alternatively, that women have 100 times more sexual partners than men. Evidence suggests otherwise.

Or put another way: you're comparing one group where 1/200 is on birth control to another group where 99/200 is on birth control. Obviously the group that has almost 100 times more people on birth control is more "efficient". That has nothing to do with sex.

But to address the issue of efficiency, I would expect male birth control is more "efficient", as women can only carry a few children at a time while men can theoretically impregnate dozens or even hundreds of women in the same period.

But I find the quibbling over efficiency to be missing the point. Male contraception offers peace of mind to some. It has nothing to do with efficiency.