Please answer the given financial question based on the context.
Context: 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 .
Question: how much did the s&p 500 index decline in the fourth quarter?


Answer: The answer is:0.28961