Throughout history we've seen how important it was for a woman to be unspoiled untill she married and found a husband. At what point in history did it stop being important that the woman should be a virgin?
Sex & Society journal reports that the Roaring 20s were the turning point for Americans, though premarital sex always happened. According to that journal, more than half of women who married before WWI were virgins at marriage (and many of the remainder had sex only with their fiance before the marriage). But the percentage of virgins at marriage dropped to 11% by 1960.
Even before that, the majority wasn't strong. Oxford's Magazine of History Journal reports that 30-40% of brides in colonial America were pregnant on their wedding day.