Year % 1984 16.277039502766293 1985 20.425805056804908 1986 25.398825089698573 1987 29.622168122479138 1988 34.60130427583653 1989 40.20310538882179 1990 45.05556489472254 1991 44.89655592962685 1992 45.15963855152366 1993 46.959699904554114 1994 48.95257227062625 1995 52.24142681363573 1996 51.973289118267004 1997 55.25911843768154 1998 56.6458063887809 1999 57.84354915839795 2000 61.552105631076735 2001 62.8862849049895 2002 66.68904587170722 2003 68.60433701513269 2004 70.64790589638446 2005 72.35118162150036 2006 74.31688416449798 2007 75.43958043715007 2008 77.40572727597322 2009 81.05241990383011 2010 79.35556490303289 2011 75.9121094701809 2012 74.12513043580707 2013 74.97924775408306 2014 76.1110087832713 2015 76.91810074659101 2016 76.95293237941532 2017 79.60867893313645 2018 80.70045599206074 2019 80.45403840975325 2020 81.15019775777291 2021 80.21250196178967 2022 79.66733340386158