From one of my links this week:
Reagan tax cuts - 1982. Bush tax cuts - 2001 and 2003. Clinton tax increase on the wealthy - 1993. Extension of Bush tax cuts - 2012. Capital gains taxes were decreased to 28% in 1978, went down to 20% in 1997, and down to 15% in 2003. Dividend tax rates went from ordinary income rates (as high as 35-39.6%) to 15% in 2003. A coincidence between these changes in the tax code and the chart above? I think not.