Year Percent 1987 5.25 1988 5.14 1989 5.76 1990 4.1 1991 5.18 1992 5.63 1993 5.85 1994 5.44 1995 5.38 1996 7.98 1997 6.92 1998 8.38 1999 10.26 2000 3.8433 2001 3.6181 2003 5.3574 2004 4.5309 2005 3.1777 2006 3.0159 2007 2.6348 2008 3.1985 2009 3.7706 2010 3.5202 2011 2.9255 2012 2.8518 2013 2.7047 2014 3.0566 2015 3.005 2016 3.7025 2017 3.0491