[ChuckMcM]

But then there are family crypts with 4, 6, 8, 12 bodies interred pulling the average down. Not to mention the number of people who have been interred and then the cemetary later moved because it was on land deemed desirable to the developer (and of course a standard trope of many horror movies). So I doubt the dead could "crowd out" the living but they could certainly end up stacked in a cave somewhere far away from their original burial.