Year Percent 1990 97.47 1991 97.463 1992 97.506 1993 97.119 1994 97.388 1995 97.319 1996 97.399 1997 97.459 1998 97.08 1999 96.891 2000 96.666 2001 96.669 2002 96.668 2003 96.587 2004 96.474 2005 96.837 2006 97.149 2007 97.329 2008 97.153 2009 97.458 2010 95.397 2011 95.879 2012 96.006 2013 96.119 2014 96.035 2015 96.781 2016 97.62 2017 97.523 2018 97.429 2019 97.337 2020 97.245 2021 97.154 2022 97.063 2023 96.972 2024 96.883 2025 96.795 2026 96.708 2027 96.622 2028 96.536 2029 96.446 2030 96.351