Thanks!
I'm starting to get it! I will have to divide the heat given during crystallization by 293g/J (other sources give the same amount). To make sure, I added an attachment of a DSC of one of my materials. The heat during crystallization is 38,7 g/J.
=> 38,7/293 = 0,13 => 13%
Purple is the first heating, black cooling, green second heating