Year Percent 1990 41.444 1991 41.453 1992 41.445 1993 41.47 1994 41.5 1995 42.272 1996 43.047 1997 43.826 1998 44.608 1999 45.392 2000 46.179 2001 46.968 2002 47.759 2003 48.55 2004 49.342 2005 50.135 2006 50.927 2007 51.719 2008 52.51 2009 53.3 2010 46.91 2011 47.03 2012 51.38 2013 48.81 2014 48.25 2015 44.82 2016 48.15 2017 48.216 2018 48.281 2019 48.347 2020 48.413 2021 48.479 2022 48.544 2023 48.61 2024 48.676 2025 48.741 2026 48.807 2027 48.873 2028 48.939 2029 49.004 2030 49.07