You can calculate %age Crystallinity using the steps as mentioned in the attached document. You need to redefine the region of the amorphous hump and the concerned characteristic peaks of the region. The Area of the amorphous and crystalline peak can be obtained using the method and therefore you will simply have to use the % Crystallinity formulae to calculate your results.
% Crystallinity = (total area of crystalline peaks) x 100 / (total area of all peaks)