In women, progesterone levels are relatively low during the preovulatory phase of the menstrual cycle, rise after ovulation, and are elevated during the luteal phase, as shown in diagram below. Progesterone levels tend to be < 2 ng/ml prior to ovulation, and > 5 ng/ml after ovulation.
Results for this Gallup poll are based on telephone interviews conducted Aug. 7-Dec. 29, 2013, on the Gallup Daily tracking survey, with a random sample of 3,445 adults, aged 18-34, living in all 50 U.S. states and the District of Columbia, who report they are currently living at home with their parents.
I'm pretty sure it's 18. When you move out at 18, your parents can call the cops or try other ways to get you back into the house but by law you are considred and adult therefore there is nothing they can do.