Problem with your graph
and I can't completely discredit it of course, is that during all of those years the population of our country was growing. Economic growth should have a continual slow rise along with that population increase. We should really see the overall plot of the curve following a natural slope with only minor blips. The last few years show something that really hasn't happened over the period shown.
Of course all areas reach a limit where the overpopulation reaches such a level that economic stagnation takes over as the resources run out. So maybe the trend is completely natural and we should instead target the Catholics and Mormons instead of the Bush administration.
Art