Year Percent 1990 93.858 1991 93.909 1992 93.936 1993 93.998 1994 94.044 1995 94.391 1996 94.715 1997 95.013 1998 94.701 1999 94.358 2000 93.976 2001 93.557 2002 93.097 2003 92.599 2004 92.072 2005 91.516 2006 91.976 2007 92.377 2008 92.918 2009 93.192 2010 92.595 2011 93.388 2012 92.394 2013 92.359 2014 92.335 2015 92.36 2016 92.387 2017 92.4 2018 92.419 2019 92.44 2020 92.46 2021 92.481 2022 92.5 2023 92.516 2024 92.523 2025 92.519 2026 92.506 2027 92.482 2028 92.447 2029 92.403 2030 92.35