Year Percent 1990 53.365 1991 53.763 1992 54.786 1993 55.538 1994 55.936 1995 56.585 1996 57.352 1997 58.219 1998 59.032 1999 59.789 2000 60.419 2001 60.844 2002 61.447 2003 61.597 2004 61.875 2005 62.713 2006 63.624 2007 64.464 2008 63.091 2009 61.688 2010 63.344 2011 65.952 2012 66.457 2013 68.145 2014 68.968 2015 69.762 2016 70.395 2017 70.596 2018 70.797 2019 70.999 2020 71.202 2021 71.409 2022 71.616 2023 71.822 2024 72.026 2025 72.228 2026 72.431 2027 72.632 2028 72.83 2029 73.028 2030 73.227