what was the difference in percentage return for lilly compared to the peer group for the five years ended dec-18?
performance graph this graph compares the return on lilly stock with that of the standard & poor 2019s 500 stock index and our peer group for the years 2014 through 2018 . the graph assumes that , on december 31 , 2013 , a person invested $ 100 each in lilly stock , the s&p 500 stock index , and the peer groups' common stock . the graph measures total shareholder return , which takes into account both stock price and dividends . it assumes that dividends paid by a company are reinvested in that company 2019s stock . value of $ 100 invested on last business day of 2013 comparison of five-year cumulative total return among lilly , s&p 500 stock index , peer group ( 1 ) .

|  | Lilly | Peer Group | S&P 500 |
| :--- | :--- | :--- | :--- |
| Dec-13 | $100.00 | $100.00 | $100.00 |
| Dec-14 | $139.75 | $114.39 | $113.69 |
| Dec-15 | $175.21 | $116.56 | $115.26 |
| Dec-16 | $157.03 | $112.80 | $129.05 |
| Dec-17 | $185.04 | $128.90 | $157.22 |
| Dec-18 | $259.88 | $136.56 | $150.33 |

( 1 ) we constructed the peer group as the industry index for this graph . it comprises the companies in the pharmaceutical and biotech industries that we used to benchmark the compensation of our executive officers for 2018 : abbvie inc. ; amgen inc. ; astrazeneca plc ; baxter international inc. ; biogen idec inc. ; bristol-myers squibb company ; celgene corporation ; gilead sciences inc. ; glaxosmithkline plc ; johnson & johnson ; medtronic plc ; merck & co. , inc. ; novartis ag. ; pfizer inc. ; roche holdings ag ; sanofi ; and shire plc. .

lilly_return = 259.88
peer_group_return = 136.56
s_and_p_500_return = 150.33
initial_investment = 100
percent_change_lilly = (lilly_return - initial_investment) / initial_investment
percent_change_peer_group = (peer_group_return - initial_investment) / initial_investment
percent_change_s_and_p_500 = (s_and_p_500_return - initial_investment) / initial_investment
percent_change_difference = percent_change_lilly - percent_change_peer_group
answer = percent_change_difference * 100