The 85% of women that have problems with desire? That came from a poll that was done of 1000's of women. It bascially said that 85% of women will essentially be ND at some point in life (some temporary, some permanent).
As for PM, it does have somewhere in that book the statement that only 20% of marriages can really achieve the status of PM, mainly because it is so hard to achieve. Since 50 % of marriages end in divorce, this means that 3/5 of the couples that don't divorce, essentially just give up on the PM, and just stay together, like COMPANIONS.
