I don't have any data, but I never really 100% trust the NPT moorings. At least the Moor secure moorings have a business reason for making their tackle reasonably safe and inspecting it (fairly) regularly. I'm not sure that the gov't has the same motivation and ability. Also the NPT moorings are found in less desirable and more challenging anchoring areas close to attractions rather than close to protection.

The Baths and to a lesser extent the Indians stand out for me as areas that have got to be hard on mooring tackle with all of the daily use in often times heavy groundswell conditions. IMHO a prudent mariner should think twice about using these moorings overnight (often seen at the Indians) or in unsettled conditions without someone competent on board.