Year Percent 1990 93.606 1991 93.683 1992 93.803 1993 93.89 1994 93.968 1995 94.02 1996 94.057 1997 94.079 1998 94.085 1999 94.067 2000 94.028 2001 93.97 2002 93.895 2003 93.813 2004 93.733 2005 93.668 2006 93.615 2007 93.567 2008 93.527 2009 93.493 2010 93.465 2011 93.444 2012 93.428 2013 93.422 2014 93.425 2015 93.437 2016 93.46 2017 93.484 2018 93.511 2019 93.534 2020 93.55 2021 93.561 2022 93.564 2023 93.562 2024 93.554 2025 93.541 2026 93.526 2027 93.506 2028 93.48 2029 93.443 2030 93.397