A sample of 50 11th graders were asked to select a favorite pattern out of 6 choices. The data below shows what their favorite color patterns were, and the accompanying frequency table and bar graph represent these data. In the bar graph, the height of the blue-gray bar is 4, the height of the green bar is 9, and so on.
\begin{tabular}{|c|c|}
\hline Color Pattern & Frequency \\
\hline Blue on gray & 4 \\
\hline Green & 9 \\
\hline Pink polka dots & 14 \\
\hline Purple & 11 \\
\hline \begin{tabular}{c}
Red and orange \\
stripes
\end{tabular} & 9 \\
\hline Yellow & 3 \\
\hline
\end{tabular}
Suppose that, rather than being just a bar graph, the display you see above is a relative frequency bar graph. The vertical axis of the graph will be marked off in percentages, from 0 percent up to 30 percent. What will be the height of the purple bar?