In December 2015, Ames, Iowa, had the lowest unemployment in the United States at 2.2 percent of the workforce. At the other end of the scale was El Centro, California, with 19.6 percent of its workforce unemployed. In the depths of the 2008-2009 recession, the unemployment rate in Ames peaked at 5.7 percent. In El Centro, it reached a high of 30.3 percent.

How would you explain the difference in unemployment rates in Ames and El Centro in December 2015? Why is the difference almost certainly not explained by different cyclical unemployment rates?