Year Percent 1990 3.37 1991 3.64 1992 2.47 1993 1.69 1994 1.68 1995 1.72 1996 1.51 1997 1.31 1998 1.31 1999 1.26 2000 0.99 2001 1.01 2002 0.96 2003 1.27 2004 1.31 2005 1.44 2006 1.14 2007 1.17 2008 1.63 2009 1.51 2010 1.6 2011 1.83 2012 1.76 2013 1.7 2014 2.02 2015 2.57 2016 2.67 2017 3.58 2018 3.99 2019 4.56