We have people named Rasmussen and both they and everyone I've heard pronounce it as Rass  muss sen but on TV and radio there is a group that run a poll and when I hear the talking heads they say rass mooo sen.

I guess it's like pop, soda and coke.  I found it funny to ask for a coke and be asked what kind, thinking cherry, diet or regular when they meant Pepsi, Coke or something else.