The density of an amorphous polymer is $0.77 \mathrm{~g} \mathrm{~cm}^{-3}$ and that of its crystalline counterpart is $0.99 \mathrm{~g} \mathrm{~cm}^{-3}$. The density of a semi-crystalline sample of this polymer is found to be $0.88 \mathrm{~g} \mathrm{~cm}^{-3}$.
The degree of crystallinity (on weight basis) of this semi-crystalline sample is $\_\_\_\_\_\_\_\_$. (Round off to two decimal places)
