Year Percent 1990 4.83078 1991 4.97399 1992 4.90375 1993 4.95763 1994 4.68088 1995 4.49853 1996 4.32994 1997 3.60066 1998 3.61989 1999 3.50984 2000 3.35741 2001 3.38635 2002 3.72048 2003 3.67952 2004 3.32723 2005 3.34711 2006 3.19241 2007 3.19997 2008 3.19952 2009 2.81718 2010 2.94823 2011 2.97676 2012 2.9902 2013 3.06013 2014 3.05348 2015 3.0685 2016 3.04401 2017 3.07134 2018 3.1277 2019 3.10436 2020 3.16551