Year Percent 1990 2.083 1991 0 1992 0 1993 0 1994 0 2004 1.9878 2005 0.6072 2006 1.6501 2007 1.1336 2008 1.7806 2009 1.9733 2010 1.6398 2011 1.7217 2012 1.7424 2013 1.5707 2014 2.1644 2015 2.2197 2016 2.2705 2017 2.3856