Depends on your timeframe. The S&P returned -22% from 1/1/2000 to 1/1/2010, and only +43% from 1/1/2000 to today. The annualized return is nowhere near the 11% quoted in the article.
-5.65% from 1/2000 to 1/2010 with dividend reinvestment
+89.85% from 1/2000 to 12/2014 with dividend reinvestment
The annualized returns are generally over rolling 30 year periods. which 12/1984 to today is 8.79% without reinvestment or 11.32% with reinvestment of dividends.
They'll be a bit lower once you factor in taxes, which can be a sizable chuck (especially because that tax difference "compounds" year over year in the reinvestment case)
http://www.nytimes.com/interactive/2011/01/02/business/20110...