Tim,
There was a good article some time ago, I think in the NYT, listing some of the courses that were, or were going to be, closed.
MB was trucking along nicely with ca. 100 courses sharing 4 million rounds. Then 7 new courses were built (with no increase in the number of rounds), cutting the 'share' by 2,600 rounds per course, with the new venues benefitting from their advertising 'hype'.