Bret, here's a different perspective on the statistics (which I came across in 2 minutes of searching on the Internet). I have no idea who the author is, but his numbers seem just as good as yours. He concludes:
"Nobel laureate Robert Lucas, one of the world's most famous conservative economists, has spent over a decade looking for the secret to economic growth, and has not found it. Nobel-bound Paul Krugman, one of the world's most famous liberal economists, admits that the mystery of growth is "deep and poorly understood." People who claim that tax rates affect growth are not serious economists; more often they are journalists, radio-talk show hosts, politicians and other types of snake oil salesmen with easy solutions to complex problems. You can dismiss their bumper sticker slogans with perfect confidence."
My point is not to argue about the data. In fact, I suspect a good statistician can pretty much prove anything by drawing selectively from the huge pool of existing economic data (with the possible exception that communism worked out well).
I was reading a presentation this morning about how good ideas get transmitted in a corporation. In fact, presentation of charts and data have very little impact in driving improvements. Story-telling is where the real leverage comes from. This may be good news for Harvard grads, and not so good news for MIT grads. It also may explain why people from MIT are often considered nerds who are so attuned to the data that they are out of touch with the stories of "real" life. I certainly can acknowledge that this has been an occasional fault of mine.