If plotted, the following sales series would appear curvilinear. This indicates that sales are increasing at a somewhat constant annual rate (percent). To fit the sales, therefore, a logarithmic equation should be used.

a. Determine the logarithmic equation.
b. Determine the coordinates of the points on the logarithmic straight line for 2005 and 2011.
c. By what percent did sales increase per year, on the average, during the period from 2004 to 2014?
d. Based on the equation, what are the estimated sales for2015?