human
table of contents the following performance graph is not 201csoliciting material, 201d is not deemed filed with the sec, and is not to be incorporated by reference into any of valero 2019s filings under the securities act of 1933 or the securities exchange act of 1934, as amended, respectively. this performance graph and the related textual information are based on historical data and are not indicative of future performance. the following line graph compares the cumulative total return 1 on an investment in our common stock against the cumulative total return of the s&p 500 composite index and an index of peer companies (that we selected) for the five-year period commencing december 31, 2008 and ending december 31, 2013. our peer group comprises the following 11 companies: alon usa energy, inc.; bp plc; cvr energy, inc.; delek us holdings, inc. (dk); hollyfrontier corporation; marathon petroleum corporation; pbf energy inc. (pbf); phillips 66; royal dutch shell plc; tesoro corporation; and western refining, inc. our peer group previously included hess corporation, but it has exited the refining business, and was replaced in our peer group by dk and pbf who are also engaged in refining operations. comparison of 5 year cumulative total return1 among valero energy corporation, the s&p 500 index, old peer group, and new peer group.
|  | 12/2008 | 12/2009 | 12/2010 | 12/2011 | 12/2012 | 12/2013 |
| --------- | --------- | --------- | --------- | --------- | --------- | --------- |
| Valero Common Stock | $100.00 | $79.77 | $111.31 | $102.57 | $170.45 | $281.24 |
| S&P 500 | 100.00 | 126.46 | 145.51 | 148.59 | 172.37 | 228.19 |
| Old Peer Group | 100.00 | 126.98 | 122.17 | 127.90 | 138.09 | 170.45 |
| New Peer Group | 100.00 | 127.95 | 120.42 | 129.69 | 136.92 | 166.57 |
____________ 1 assumes that an investment in valero common stock and each index was $100 on december 31, 2008. 201ccumulative total return 201d is based on share price appreciation plus reinvestment of dividends from december 31, 2008 through december 31, 2013. .
Please compute the result.
what is the value of an investment in valero common stock	in 2010?
assistant
111.31
human
what about in 2009?
assistant
79.77
human
what is the difference in the value?
assistant
31.54
human
what is the value of an investment in valero common stock	in 2009?
assistant
79.77
human
what percentage does this represent?
assistant
0.39539