Year Percent 1990 62.141 1991 62.061 1992 62.137 1993 61.718 1994 61.16 1995 59.955 1996 59.38 1997 58.125 1998 58.004 1999 57.866 2000 59.285 2001 59.975 2002 58.682 2003 58.256 2004 57.549 2005 57.959 2006 56.747 2007 56.43 2008 56.883 2009 57.716 2010 58.9 2011 59.229 2012 60.046 2013 60.451 2014 61.399 2015 61.711 2016 62.244 2017 62.502 2018 62.767 2019 63.027 2020 63.275 2021 63.52 2022 63.749 2023 63.96 2024 64.146 2025 64.305 2026 64.443 2027 64.552 2028 64.634 2029 64.689 2030 64.721