Year Percent 1980 0.00828 1993 0.22531 1994 0.34428 1995 0.29832 1996 0.26389 1997 0.0825 2004 1.32691 2005 1.07217 2006 0.74766 2007 1.08167 2008 1.15629 2009 0.41683 2010 0.55433 2011 1.01197 2012 0.81543 2013 1.21769 2014 1.16607 2015 1.05414 2016 -1.24367 2017 0.20163