Year Percent 1982 1.97 1983 2.38 1984 2.66 1985 3.06 1986 2.74 1987 2.86 1988 3.01 1989 2.52 1990 4.71 1991 4.97 1992 5.8 1993 7.28 1994 3.42 1995 3.89 1996 4.6 1997 5.16 1998 6.36 1999 4.75 2000 6.74 2001 5.55 2002 5.75 2003 6.07 2004 5.07 2005 3.97 2006 4.02 2007 3.45 2008 2.25 2009 2.72 2010 2.47 2011 3.59 2012 3.44 2013 3.78 2014 3.82 2015 4.72 2016 4.97 2017 4.24 2018 3.85 2019 3.39 2020 4.03