This is very interesting and you should go check it out. The dive in both marriages and divorces during the Great Depression (presumably because both of those things cost money, which people were somewhat lacking), the huge spike in marriage and almost concurrent spike in divorces around the end of WWII, and the steadily declining rates of both marriage and divorce in more recent years all stand out.
In fact, the author even points out, "Looking to more recent history, there has been a steady decline in marriage rates (and consequently, divorce rates) since the 1980s, with no sign of slowing down. In fact, when taking population into account, marriage rates in the U.S. are now at the lowest they’ve ever been in recorded U.S. history — even lower than during The Great Depression!"
Basically just go read it.