Year Percent 1987 5.83389 1988 6.34124 1989 6.2512 1990 4.28139 1991 3.23154 1992 1.90944 1993 1.71236 1994 1.65436 1995 1.62051 1996 1.77695 1997 1.63873 1998 1.90654 1999 1.83501 2000 2.02248 2001 1.78166 2002 1.79557 2003 1.50969 2004 1.38273 2005 1.18083 2006 1.13847 2007 1.31284 2008 1.17206 2009 0.82379 2010 0.763 2011 0.83727 2012 0.92431 2013 0.82231 2014 0.85963 2015 0.86561 2016 0.84837 2017 0.7371