Year | Value | 2022 | 14.427 | 2021 | 15.779 | 2020 | 16.553 | 2019 | 17.393 | 2018 | 21.2 | 2017 | 22.814 | 2016 | 24.297 | 2015 | 26.433 | 2014 | 28.381 | 2013 | 29.138 | 2012 | 31.199 | 2011 | 31.502 | 2010 | 33.135 | 2009 | 32.351 | 2008 | 33.93 | 2007 | 35.231 | 2006 | 36.392 | 2005 | 37.32 | 2004 | 37.161 | 2003 | 36.69 | 2002 | 31.94 | 2001 | 30.52 | 2000 | 32.2 | 1999 | 32.4 | 1998 | 34.5 | 1997 | 36 | 1996 | 38.8 | 1995 | 35.6 | 1994 | 30 | 1993 | 27.7 | 1992 | 26.3 | 1991 | 24.5 | 1990 | 23.6 | 1989 | 22.6 | 1988 | 21.4 | 1987 | 21.5 | 1986 | 21.7 | 1985 | 21.6 | 1984 | 21.1 | 1983 | 20.9 | 1982 | 22 |
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