Year Percent 1991 0.02648 1992 0.15199 1993 0.03165 1999 1.12098 2000 0.70844 2001 1.96507 2005 1.87149 2007 1.07038 2008 3.20279 2012 3.71069 2013 3.17758 2014 8.46341 2016 2.32147