Year Percent 1983 0.57732 1984 0.73117 1985 1.176 1986 1.37387 1987 1.19933 1988 0.19362 1989 1.23575 1990 2.14859 1991 1.08718 1992 0.41517 1993 0.6457 1994 1.25841 1995 1.21367 1996 1.32477 1997 2.54999 1998 3.27038 1999 4.28612 2000 8.48389 2001 3.50464 2002 2.73974 2003 5.58805 2004 1.80186 2005 0.65206 2006 12.47578 2007 10.14523 2008 0.53953 2009 8.80111 2010 3.02694 2011 2.96814 2012 5.97917 2013 -3.62038 2014 2.96159 2015 17.06072 2016 9.04342 2017 5.57735