Using your favorite statistics software package, you generate a scatter plot with a regression equation and correlation coefficient. The regression equation is reported as $\displaystyle {y}={21.41}{x}+{77.16}$ and the $\displaystyle {r}={0.663}$.

What proportion of the variation in y can be explained by the variation in the values of x?
r² = %

Report answer as a percentage accurate to one decimal place.