After a quick search, here are the percentages of women who masturbate according to age bracket:   
Under 16=65 
17-19=71 
20-24=73 
25-34=75 
35-43=63 
44-50=60 
51-57=45 
58-64=30 
65+=25     
Now, that is MOST women. So why do MOST women lie about it? Silly bints.