I'm not aware of an API, but they way they have it set up it's pretty easy to gather data via a technique called screen/web scraping.
For example, a search on your name gives a link to a specific page with your member id in the URL. Then if you have a programming language/library that is DOM-aware, you can simply figure out where certain things will be, based on the design of the page. Using jquery selectors, and a couple of traversals, that page can be parsed to get the rating as such:
> $("td td td:contains(Regular Rating)").next().find("nobr").text();
2012-03(Current floor is 1800)"
Nice rating, by the way.
It's a bit painful, and even more painful if they ever decide to change the design of the pages, but eventually you'll be able to parse out all the data you want, and then build a way of collecting data for each member and storing it in your own database for analytics. It wouldn't be that hard to do, just iterate through member ids, and you can get their names, states, ratings, etc.--as much is available on their screens.
Hope that helps.