Don't know, I have been married 31 years lays potato chip,you can't eat it just once, or.daily bread you needed it every day, after about 10 years of being married she we were still doing it a lot just like when we 1st got married. I replied how do know that and she had been marking it on her calendar in her diary and we were still averaging 25 times a month and we 32 times a month at 1st