Year Percent 1990 97.792 1991 97.738 1992 97.681 1993 97.621 1994 97.552 1995 97.474 1996 97.387 1997 97.29 1998 97.181 1999 97.058 2000 96.918 2001 96.771 2002 96.611 2003 96.446 2004 96.288 2005 96.141 2006 96.007 2007 95.881 2008 95.756 2009 95.617 2010 95.455 2011 95.387 2012 95.321 2013 95.252 2014 95.184 2015 95.119 2016 95.061 2017 94.983 2018 94.915 2019 94.853 2020 94.795 2021 94.744 2022 94.696 2023 94.653 2024 94.613 2025 94.576 2026 94.543 2027 94.51 2028 94.475 2029 94.429 2030 94.368