Year % 1981 5.997329876222369 1982 6.284361767613037 1983 8.083637004261666 1984 9.77937964186377 1985 15.130809419338913 1986 22.794411527891015 1987 31.671850648961563 1988 32.97560036570924 1989 38.03884431830465 1990 43.536472633251435 1991 46.123176904498195 1992 49.13531601432738 1993 50.10672508384219 1994 50.31544789586512 1995 53.02692936356166 1996 54.58246226851696 1997 58.26136198617939 1998 59.5288168016496 1999 60.50008165856407 2000 63.913030957502066 2001 66.21431811383627 2002 69.5294310359186 2003 70.30129921650993 2004 69.98798650771897 2005 70.44989993219609 2006 72.08082737267308 2007 71.46724271194594 2008 73.11426758787482 2009 76.15293390515515 2010 77.00355694196722 2011 68.24353904131786 2012 68.84046026965228 2013 68.74002096540826 2014 67.16227883797562 2015 67.44390656320519 2016 69.23464545060881 2017 72.0209930479855 2018 74.13278355039448 2019 73.95625285467176 2020 76.10244625296129 2021 76.16327210440532 2022 76.97243637077997