stock total return performance the following graph compares our total return to stockholders with the returns of the standard & poor 2019s composite 500 index ( 201cs&p 500 201d ) and the dow jones us select health care providers index ( 201cpeer group 201d ) for the five years ended december 31 , 2014 . the graph assumes an investment of $ 100 in each of our common stock , the s&p 500 , and the peer group on december 31 , 2009 , and that dividends were reinvested when paid. .