human
2 0 0 8 a n n u a l r e p o r t stock performance graph the following graph sets forth the performance of our series a common, series b common stock, and series c common stock for the period september 18, 2008 through december 31, 2008 as compared with the performance of the standard and poor 2019s 500 index and a peer group index which consists of the walt disney company, time warner inc., cbs corporation class b common stock, viacom, inc. class b common stock, news corporation class a common stock, and scripps network interactive, inc. the graph assumes $100 originally invested on september 18, 2006 and that all subsequent dividends were reinvested in additional shares. september 18, september 30, december 31, 2008 2008 2008.
|  | September 18,   2008 | September 30,   2008 | December 31,   2008 |
| --------- | --------- | --------- | --------- |
| DISCA | $100.00 | $103.19 | $102.53 |
| DISCB | $100.00 | $105.54 | $78.53 |
| DISCK | $100.00 | $88.50 | $83.69 |
| S&P 500 | $100.00 | $96.54 | $74.86 |
| Peer Group | $100.00 | $92.67 | $68.79 |
s&p 500 peer group.
Please answer the following questions with expressions if necessary.
what was the value of discb stock on december 31, 2008?
assistant
78.53
human
what is the value of discb stock on december 31 2008 less the initial investment?
assistant
subtract(78.53, const_100)
human
what is the percent change?
assistant
subtract(78.53, const_100), divide(#0, const_100)