So, to answer the question, with some very simple variables
filled, and assuming that the statistics given are culturally constant...
There are 6000000000 people (given), and that 51% of the population is represented by the female gender, 49% by the male (given), and 95% of men masturbate, 60% of women (cite: Seumas). This should be sufficient to answer the question.
2940000000 x 0.95 = Number of men who masturbate = 2793000000
3060000000 x 0.60 = Number of women who masturbate = 1836000000
Which, expressed as a ratio is 1.521:
1.521 men/women masturbate.
For every woman passing the finger, there is a man-and-a-half whacking off.
Alternately, one could read the question as "How many men masturbate over women?" This will require more field research, and much less theory.