a major flaw with this and most of the OP is it focuses basically only on presidents....ignoring who runs congress
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The Democratic Dividend
The stock market prefers Democratic presidents to Republicans.
Democrats, it turns out, are much better for the stock market than Republicans. Slate ran the numbers and found that
since 1900, Democratic presidents have produced a 12.3 percent annual total return on the S&P 500, but Republicans only an 8 percent return. In 2000, the Stock Trader's Almanac, which slices and dices Wall Street performance figures like baseball stats, came up with nearly the same numbers (13.4 percent versus 8.1 percent) by measuring Dow price appreciation. (Most of the 20th century's bear markets, incidentally, have been Republican bear markets: the Crash of '29, the early '70s oil shock, the '87 correction, and the current stall occurred under GOP presidents.)
According to almanac editor Jeffrey Hirsch, the presidential party figures are among the most significant he's found. If the stock market were random, we'd expect such a result only one-quarter of the time. "I don't know why people are convinced Republicans are good for the stock market," Hirsch says.
Nor does having a Republican Congress help the market. A Democratic Senate showed returns of 10.5 percent (versus 9.4 percent for a GOP upper chamber), and a Democratic House returned 10.9 percent versus 8.1 percent for the Republicans.
When both houses of Congress opposed the president, the return was a stellar 12.9 percent. Libertarians may celebrate this as proof that the market likes gridlock and government inaction. But the market likes steamrollers nearly as much: The S&P performs almost as well—returning 11.8 percent—when the presidency and both houses are held by the same party. The only situation Mr. Market dislikes is what we have now: one house for each party. Those years have a -0.9 percent return.
Republicans are no doubt muttering that that's just the stock market, not the whole economy. But real GDP growth follows the same pattern. Since 1930 (the first year decent data is available), GDP growth was 5.4 percent for Democratic presidents and 1.6 percent for Republicans.
http://www.slate.com/?id=2071929