Here is the turnout factor from 2008, and a results comparison with 2012 (all results from before Feb 10, when most candidates still in, list by date):
caucus:
Iowa 10% (21% in 2012)
Nevada 14%
Maine 18%
Alaska 17%
Colorado 9%
Minnesota 16%
Montana 25%
North Dakota 21%
Washington 22%
Kansas 11%
primary:
New Hampshire 8% (23% in 2012)
Michagan 6%
South Carolina 4% (13% in 2012)
Florida 3%
Alabama 3%
Tennessee 6%
Connecticut 4%
Arizona 4%
Georgia 3%
Delaware 4%
California 4%
Arkansas 5%
etc.
The lowest caucus was 9%, the highest primary was 8%.
The highest caucus was 25%, the lowest primary was 3%.
Turnout can make a huge difference.