Solution:

For a solid sphere, $I = \frac{2}{5}MR^2$. Rotational kinetic energy is $\frac{1}{2}Iomega^2 = \frac{1}{5}MR^2\omega^2$ and total kinetic energy is $\frac{7}{10}MR^2\omega^2$. Ratio is $\frac{2}{7}$.