Year Percent 1990 52.464 1991 53.489 1992 55.158 1993 55.828 1994 57.219 1995 58.141 1996 59.488 1997 61.171 1998 62.415 1999 64.268 2000 65.624 2001 66.842 2002 67.711 2003 68.537 2004 69.172 2005 69.933 2006 70.67 2007 72.241 2008 73.351 2009 74.051 2010 72.578 2011 72.821 2012 73.885 2013 74.282 2014 73.768 2015 74.653 2016 74.969 2017 75.223 2018 75.462 2019 75.703 2020 75.953 2021 76.209 2022 76.47 2023 76.738 2024 77.017 2025 77.31 2026 77.614 2027 77.93 2028 78.258 2029 78.598 2030 78.95