Your 99% number is a talking point that's not reflective of reality. Pew did an excellent study of what global Muslims believe and it's actually pretty troubling. It will take less than 5 minutes to google it.
At any rate, the better question is this: is Sharia law compatible with western values?
The short answer is it depends on which Muslim you ask. Muslims who advocate Sharia for non-Muslims are a threat to democracy; ironically, I'd wager many Muslims would advocate they not be allowed into this country.
Conversely, those Muslims who believe it's a set of laws pertaining only to Muslims would do just fine in a democracy.
As far as the numbers go, if just one percent of the global Muslim community believes Sharia pertains to everyone, you are talking about millions of Muslims, since the total population is in the billions. In other words, this isn't Fred Phelps and his little band of fringe Christians we're talking about here.
And the 1% number is almost certainly low. It's a real problem.