Were ppl really more chaste in the 1930's,40's, and 50's than they are now?

you always hear about the decades imediately before the 1960's as being about ppl repressing their uality and then in the 1960'a ppl embrased it instead. Was there really just as much premarital in the decades just before the 1960's as their is today? I know that the stats for north america as of 2006 say that about 87% of north americans engage in premarital .