[bodyfour]

If the chart had been adjusted for population, the decline would been even more dramatic. 1950's $20B (2011) USD was in a country slightly less than half the size of the US today.

In fact, if you look at the curve from 1950-2000 you see it seems to approximately track the population growth from 1950, with a weird peak in ~1990 and trough a few years later. My hunch is that the previous state of the industry was that it reliably took in ~$130/yr/US resident (again, in current dollars) year after year. Now it takes in less than half that, and it's plummeting.