Transcript text: \begin{tabular}{|l|r|r|r|r|r|r|r|r|r|}
\hline year & 1998 & 1999 & 2000 & 2001 & 2002 & 2003 & 2004 & 2005 & 2006 \\
\hline sales & 299 & 326 & 347 & 362 & 371 & 374 & 371 & 362 & 347. \\
\hline
\end{tabular}
What was the average rate of change of annual sales
a) Between 2001 and 2002
$\square$ millions of dollars/year
b) Between 2001 and 2006
$\square$ millions of dollars/year