I've lived on the east coast, west coast, mid west, and the gulf coast, and have traveled to ten countries and met many Americans of various genders and races and economic backgrounds, with various levels of education, and a great number abroad as well, and in my 40 years never have I heard "nuk-u-lar" ever come out of their mouths. The only times I've heard it came at the following points in my miserable life:
1.) When I was first learning the word as a child. It came Out of my own mouth as I was trying to wrap my tiny head around the new vocabulary. The same can be said regarding some classmates at the time. Our Minnesota born and bred teacher, who did speak a little funny, set us right on "NUCLEAR," rather than "Nuk-u-lar."
2.) Out of the cartoon mouth of Homer J. Simpson.
3.) Out of the fleshy cartoon mouth of G. W. Bush.
4.) Out of the big fat mouth of Sarah the Baracuda.
I'm sure there is something like a 15% misuse of the word amongst my fellow Americans. If anyone cares to finance the research, I bet I could prove this beyond the shadow of a doubt.
However, someone is making me wonder just how many Americans they claimed to have met when they claim the majority of them say, "nuk-u-lar.'
I've yet to meet an American in China who said, "Nuk-u-lar" as opposed to "nuclear." Perhaps they can enlighten me where this tribe of "nuk-u-lar" primates lurk so I can call up Werner Herzog Fimlproduktion and get a documentary going.