Year Percent 1990 93.291 1991 93.562 1992 91.343 1993 90.995 1994 91.5 1995 90.919 1996 91.772 1997 90.718 1998 91.367 1999 91.626 2000 91.976 2001 91.782 2002 91.289 2003 90.973 2004 91.79 2005 92.122 2006 92.113 2007 91.752 2008 91.584 2009 90.34 2010 89.568 2011 89.049 2012 89.278 2013 89.224 2014 89.602 2015 89.597 2016 89.315 2017 89.265 2018 89.209 2019 89.143 2020 89.063 2021 88.971 2022 88.867 2023 88.755 2024 88.644 2025 88.537 2026 88.434 2027 88.335 2028 88.24 2029 88.149 2030 88.063