Oldies' post and Antonio's are both very true.
Let's not forget that 2000 was a horrible year for Democrats in the Mountain West. Look, just look at the 1996-2000 trend map:
As much as Democrats might have gained from 2004 on, they aren't even close to their pre-2000 levels there.
I checked Clinton's raw 1996 numbers to see if the issue was Perot and it doesn't appear to be (mainly) that:
Trend in Dem%:
I don't understand how you got these numbers.
Modified trend. I used the raw Dem % in 1996 and 2012 rather than margin for the swing. Then I subtracted 1.8% (Obama 2012 national - Clinton 1996 national) for the trend.
Ah, I see. Good job!
You got NM, wrong though. Fixed it and added a few neighboring States for comparison.
Translated on a map, with 2.5% increments (ie, the normal trend scale).