Year Percent 1990 26.50068 1991 30.48278 1992 26.05963 1993 27.10955 1994 32.34566 1995 25.34446 1996 24.96158 1997 20.12792 1998 18.148 1999 18.39951 2000 16.08486 2001 14.83746 2002 13.95464 2003 12.42566 2004 10.98802 2005 9.08684 2006 7.09157 2007 6.70298 2008 5.59581 2009 6.12193 2010 5.52125 2011 5.07565 2012 5.13977 2013 5.36626 2014 5.31941 2015 6.17745 2016 5.60495 2017 5.60737 2018 5.21251 2019 5.69526 2020 6.73895 2021 5.72598 2022 4.76455