Please answer the given financial question based on the context.
Context: performance graph the following graph compares the cumulative five-year total return provided shareholders on our class a common stock relative to the cumulative total returns of the s&p 500 index and two customized peer groups . the old peer group includes intercontinentalexchange , inc. , nyse euronext and the nasdaq omx group inc . the new peer group is the same as the old peer group with the addition of cboe holdings , inc . which completed its initial public offering in june 2010 . an investment of $ 100 ( with reinvestment of all dividends ) is assumed to have been made in our class a common stock , in the peer groups and the s&p 500 index on december 31 , 2005 and its relative performance is tracked through december 31 , 2010 . comparison of 5 year cumulative total return* among cme group inc. , the s&p 500 index , an old peer group and a new peer group 12/05 12/06 12/07 12/08 12/09 12/10 cme group inc . s&p 500 old peer group *$ 100 invested on 12/31/05 in stock or index , including reinvestment of dividends . fiscal year ending december 31 . copyright a9 2011 s&p , a division of the mcgraw-hill companies inc . all rights reserved . new peer group the stock price performance included in this graph is not necessarily indicative of future stock price performance .
||2006|2007|2008|2009|2010|
|cme group inc .|$ 139.48|$ 188.81|$ 58.66|$ 96.37|$ 93.73|
|s&p 500|115.80|122.16|76.96|97.33|111.99|
|old peer group|155.58|190.78|72.25|76.11|87.61|
|new peer group|155.58|190.78|72.25|76.11|87.61|
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Question: considering the year 2006 , what is the percentual fluctuation of the return provided by s&p 500 and the one provided by old peer group?


Answer: The answer is:39.78