This can be explained partially by smaller jumps in contraception and education than predicted, though most scientists don't fully know why the rates have stalled so much. (sciencemag.org)
It may not be related to injury, although the rupture frequently occurs after some sort of traumatic event, such as a fall or a relatively small jump. (glenerinanimalhospital.com)
It also has a fair bit of elevation change - on one section, there's even a couple of small jumps. (wtf1.com)