The Following Items Were Taken from the Financial Statements of Tilden

The following items were taken from the financial statements of Tilden, Inc., over a three-year period:
​ $\begin{array}{|l|r|r|r|}\hline \text { Item } & \text { Year 3 } & \text { Year 2 } & \text { Year 1 } \\\hline \text { Sales } & \$ 360,000 & \$ 335,000 & \$ 290,000 \\\hline \text { Cost of goods sold } & 225,000 & 205,000 & 185,000 \\\hline \text { Gross profit } & \$ 135,000 & \$ 130,000 & \$ 105,000 \\\hline\end{array}$ ​
Compute the following for each of the items listed.
​ (a) The amount and percentage change from Year 2 to Year 3.
(b) The amount and percentage change from Year 1 to Year 2. Round percentages to one decimal place.