The link is in the first comment. While this is me just talking and to answer your question more precisely would require a much bigger effort outside the scope of the summary statistics calculator, but it is likely there are network effects to divorce. If you are in a community where divorce is frequent and discussed, it is a more visible option. A community may also make it more culturally acceptable in a high divorce rate area. And folks may be drawn to certain cultural norms to begin with when choosing an area to live. Just riffing some thoughts.