Year Percent 1985 4.29081 1986 4.67442 1987 4.54187 1988 4.28038 1989 4.27683 1990 4.02623 1991 4.42402 1992 4.72739 1993 2.75961 1994 2.44369 1995 2.28118 1996 2.09575 1997 2.02481 1998 1.73292 1999 1.78293 2000 1.67058 2001 1.79159 2002 1.6741 2003 1.74126 2004 1.89764 2005 1.60235 2006 1.41343 2007 1.46828 2008 1.15019 2009 1.02088 2010 0.73792 2011 0.8555 2012 0.93668 2013 1.04639 2014 2.29084 2015 1.32762 2016 1.55497 2017 1.56558