The following table shows sales for Nike (in millions of $) for the years 2005 through 2009.

Question:

The following table shows sales for Nike (in millions of $) for the years 2005 through 2009.
Year.............2005........2006..........2007..........2008..........2009
Sales...........13,740......14,955.......16,326.........18,627.......19,176
a. Use the growth rates for 2005-2006, 2006-2007, 2007-2008, and 2008-2009 to calculate the average growth rate.
b. Calculate the average growth rate directly from sales.