Year Percent 1990 48.043 1991 48.027 1992 48.554 1993 48.727 1994 49.375 1995 49.437 1996 50.031 1997 50.025 1998 50.152 1999 50.755 2000 50.917 2001 51.156 2002 51.798 2003 52.59 2004 53.486 2005 54.106 2006 54.946 2007 55.939 2008 56.268 2009 56.35 2010 56.784 2011 57.121 2012 57.645 2013 58.11 2014 58.451 2015 58.942 2016 59.161 2017 59.337 2018 59.588 2019 59.873 2020 60.161 2021 60.464 2022 60.782 2023 61.092 2024 61.359 2025 61.563 2026 61.703 2027 61.768 2028 61.769 2029 61.73 2030 61.67