Year Percent 1990 67.063 1991 67.086 1992 67.083 1993 67.079 1994 67.104 1995 67.105 1996 67.1 1997 61.2 1998 67.2 1999 67.25 2000 67.3 2001 67.35 2002 67.4 2003 70.3 2004 68.189 2005 66 2006 72.2 2007 66.71 2008 60.726 2009 54.401 2010 53.13 2011 52.14 2012 52.75 2013 51.23 2014 51.1 2015 54.51 2016 55.5 2017 54.94 2018 54.38 2019 53.821 2020 53.261 2021 52.701 2022 52.141 2023 51.581 2024 51.021 2025 50.462 2026 49.902 2027 49.342 2028 48.782 2029 48.222 2030 47.663