Complex sentence: In the United States, studies have indicated 56% of women of reproductive age have had a partner use withdrawal by 2002 only 2.5% were using withdrawal as their primary method of contraception.
Split into simpler sentences: In the United States, studies have indicated 56% of women of reproductive age have had a partner use withdrawal. By 2002, only 2.5% were using withdrawal as their primary method of contraception.