OK I had to check, there are 60 NP and we have been to 41, there are 129 NM and we have been to 36, tho I have to say that it may have been a few more. Those Indian Ruin parks all sort of blend together over the years...heh. here are also Historical sites and I didn't bother to check those but we've been to a number of them. The NP we have not been to are mostly Alaskan or otherwise not easy to get to parks. How many have been to Dry Tortugas for example.
OK I couldn't quit there are 89 National Historical sites, we've only been to 7, 25 National Military Parks, 7 of those too and there are even more: National Recreation areas and National Memorials (seems to be a number of National Mall sites) I call it quits with them