It would also be useful to compare the socio-economic status of Muslims in the different countries. For instance, are Muslims in the U.S. more likely to be middle class than disadvantaged? As the discussion of the riots in France shows, there are issues that come up when a group is economically disadvantaged that are less likely to come up with a middle class group.

It doesn't help to compare apples and oranges; if there are differences in the demographics between the U.S. and various European countries, this should be taken into account.