In the United States, the combined oral contraceptive pill was first given to women in 1960. It was a revolutionary breakthrough in contraception for two reasons. First, it is extremely effective at preventing pregnancy if it is used in the right way. Second, it was the first contraceptive to completely separate the act of contraception (in this case the taking of a pill) from sexual intercourse itself. Unlike barrier methods, when a woman is "on the Pill," she and her man are usually not even aware of it during sexual intercourse, which seems and feels very natural. (In fact, it is possible for the woman to be on the pill without her partner even knowing.) The couple can have sex at any time they wish; they don’t need to interrupt foreplay to put birth control in place, and they can feel the physical sensations and emotional closeness of intercourse without interference from a make or female condom. Unlike coitus interruptus, when a woman is on the Pill, intercourse usually ends with her man reaching orgasm while inside the vagina, which both the man and woman usually find very pleasurable. It may also make women's menses shorter and with less bleeding, as well as helping her complexion, which most women like. For all of these reasons, the Pill is very popular. In 2005, more than 80 million women across the world used the Pill. It is the most common method of contraception in the United States, with four out of five women there having used the pill for birth control at some point in their lives. Use of the Pill is different in different countries, and among women of different ages and levels of education. Both single women and married women use the Pill in large numbers.