With thanks to the Administrative Office of the North Carolina courts, and to Stephanie Plotin of the UCLA Law Library, I can report some data on alienation of affections lawsuits in North Carolina: In fiscal years 2000-2007, there were an average of 230 such filings per year -- a bit over 0.5% of the number of all divorces, but about twice the number of product liability lawsuits, and about three-quarters of the number of wrongful death lawsuits.

Unfortunately, the table doesn't have separate categories for other torts, so I can't compare to, say, slander lawsuits and the like. The Administrative Office also stresses that this is an unverified, preliminary report; and one can certainly see how the data might be skewed in various ways, though likely in the direction of underreporting (for instance, lumping it under the general category of "intentional torts") rather than overreporting.