Well for quite some time I believe. Around 1997 was probably the first time I experienced it.
From a personal perspective I can attest to almost ending up in fights on several occasions with some of my wifes brothers (multiple) because I wasn't a muslim. It has come toe to toe and face to face on several occasions, over nothing more than me not being a muslim.
Before anyone starts critisicing me I'd like to point out the following:
1) I am agnostic.
2) My wife is a non practicing muslim (Pakistani decent, Ugandan passport)
3) Our children are mixed race, obviously.
4) I bring my children up to respect religion (Christianity and Islam) as well as atheism or agnosticism, or whatever they choose.
5) I defended my right to be with my (muslim) Pakistani wife to the point that I didn't speak to my father for several years (we only talked again because he was dying of cancer).
6) I get on with half of my wifes family... to the point where I have helped them out in many legal matters.
I believe I am qualified to comment.