The Administrative Office of the US Courts and the Federal Judicial Center collect and publish some statistics, but they're pretty basic. For example, they collect "case type" as a single field with a single value. Most cases have more than one kind of claim, so this is incredibly under-inclusive. Also there aren't codes for lots of kinds of cases.

http://www.uscourts.gov/FederalCourts/UnderstandingtheFedera... http://www.fjc.gov/

States are a grab bag but generally statistics poor.