The intro makes it appear that the described Muslims represent all Muslims in Germany. Some change from the SPIEGEL six years ago... But the article then includes some interesting data --

When dividing with the total numbers given below, it seems "Muslims" (nominal and real, a distinction not made by these diagrams) are as secular as the general population, it seems. More interesting numbers:

These however can be spun both ways:

_{*Lunatic*, n.
One whose delusions are out of fashion.}