Year Percent 1990 85.46 1991 82.88 1992 84.227 1993 85.038 1994 85.668 1995 86.369 1996 84.338 1997 85.405 1998 85.198 1999 84.957 2000 84.71 2001 84.567 2002 84.436 2003 84.299 2004 85.138 2005 84.773 2006 84.355 2007 83.883 2008 83.375 2009 82.855 2010 82.265 2011 82.207 2012 81.729 2013 81.413 2014 79.011 2015 80.235 2016 80.712 2017 80.481 2018 80.237 2019 79.999 2020 79.776 2021 79.581 2022 79.407 2023 79.247 2024 79.09 2025 78.934 2026 78.795 2027 78.668 2028 78.545 2029 78.417 2030 78.277