Year % 1981 7.4967289202135445 1982 9.162837533649295 1983 10.846741793060566 1984 13.318743530592643 1985 16.676127173813683 1986 21.723543083678653 1987 26.791221189547986 1988 30.72806130475321 1989 37.68178401738352 1990 47.95854719815842 1991 49.86592293185407 1992 50.656335621835865 1993 52.328238612581316 1994 54.439700093651766 1995 57.65969829135492 1996 58.19223910946017 1997 60.843728319466265 1998 61.248027656353344 1999 62.20179770716543 2000 65.4282683053891 2001 67.46905584102535 2002 71.24923891205597 2003 72.82947968528988 2004 75.03645667140572 2005 75.89108809851128 2006 77.3244009243156 2007 77.46648094608099 2008 79.19600931811573 2009 82.55851016384848 2010 81.34686619630264 2011 77.39208734990751 2012 76.06061894283069 2013 76.65404507520165 2014 77.56315140101167 2015 78.18234076051795 2016 78.80302968609047 2017 81.41699576987857 2018 82.15599247650898 2019 82.15335256286038 2020 82.53349939198849 2021 82.1046468109366 2022 81.60018781599193