Interesting. In my neck of the woods, contraception of any kind seems way less common than those statistics you cited earlier. At least people don't talk about it. Never happened in either my immediate family or my extended family on my side. And I'm old enough to speak for that whole 40 year span you speak of. But my Catholic in-laws up north were into it, up to and including abortion. So I am finding those statistics both troubling and perhaps a bit dubious. I will continue to look into it.
The link I shared with LearsFool a couple of clicks ago was...
http://www.guttmacher.org/media/resources/Religion-FP-tables.html
Two things about AGI: it's basically the research arm for PP. It actually has better, more accurate statistics in the pregnancy-contraceptive-abortion related field than anybody else, including the CDC. BUT it also presents those statistics to the media in a way that is, while technically accurate, operationally misleading.
If you look at the first chart at the link, you will see that there are two hugely biasing aspects which most people will hardly notice: They are surveying every woman who has ever had sex. OK, but that includes a woman who go drunk and had sex with a condom once when she was in college, and then repented and never did it that again --- counting her the same as a woman who started haing sex when she was 18 and bascally was on some contractive for the rest of her life from 18 to 48. Both these hypothetical women, and every woman in-between, simply counts as a "contraceptive user."
This is a meaningles statistic,like asking all women who have EVER driven a car, whether they have EVER run a red light, exceeded the speed limit, failed to signal, driven on the shoulder, or crossed a double yellow line. You might get a figure like 95-100%, but it wouldn't really tell you much of anything about whether most women accepted or affirmed or regularly committed traffic violations.
The second graph is just as bad, because it surveys only "sexually active women who are not pregnant, post-partum or trying to get pregnant."
Think of what this means. It means it screens out the EXACT sub-sets of women most likely to NOT use contraceptives: the abstinent, and the happily fertile married. Many married, non-contraceptive-using women spend their entire married life, practically, in one or another of these categories (trying or a least open to getting pregnant; pregnant; or postpartum). So they've excluded from the survey the precise subsets of women who would pull the numbers back in a non-contraceptive direction.
How big or small that group is, I do not know. But at least on this web page (you'll notice it's the "media center") AGI's not going to tell you.
With that in mind, you can evaluate their finding that 74% of Evangelical women are using either permanent sterilization (tubal ligation) or temporary hormonal sterilization (oral, transdermal, injected or implanted hormones). I have no doubt that's true, but true for a selected demographic slice, and not "all Evangelical women."
Nevertheless it's certain that contraceptive acceptance is overwhelming in practically all demographic subsets in the USA, with the smallish exceptions of the most devout practicing "Orthodox" believers in Christianity, Judaism, and probably Islam.