Eric Ostermeier provides analysis on the number of counties won so far by Romney, Santorum.
Santorum has won twice as many counties as Romney or 54.1% of those that report vote totals this way, according to the University of Minnesota's Smart Politics blog. The metric is "shorthand" for Santorum's support outside of urban areas, the blog says, where Romney has done well.
USA Today
April 03, 2012