Year | Value | 2021 | 25.840682820626 | 2020 | 24.415139802345 | 2019 | 25.582834918207 | 2018 | 25.417502121671 | 2017 | 25.422226176189 | 2016 | 25.419169232675 | 2015 | 26.826167415543 | 2014 | 26.417898311092 | 2013 | 26.415173094271 | 2012 | 25.92819764092 | 2011 | 25.42798527553 | 2010 | 25.281635506236 | 2009 | 25.225165236897 | 2008 | 26.077519716562 | 2007 | 25.391994315615 | 2006 | 25.050442556682 | 2005 | 25.513955464258 | 2004 | 26.308672486446 | 2003 | 26.646969932088 | 2002 | 26.975500321476 | 2001 | 27.965571988456 | 2000 | 26.225079875854 | 1999 | 26.627822201928 | 1998 | 26.889845462572 | 1997 | 26.797712169363 | 1996 | 25.940036007277 | 1995 | 24.60010616688 | 1994 | 18.345573061435 | 1993 | 18.93545576949 | 1992 | 18.920480502603 | 1991 | 18.167178555984 | 1990 | 17.981083333824 | 1989 | 17.805751869943 | 1988 | 18.562800775702 | 1987 | 17.720084156553 | 1986 | 17.972336757981 | 1985 | 18.103784077415 | 1984 | 18.964077512268 | 1983 | 18.032588784856 | 1982 | 18.190420396576 | 1981 | 18.949825648524 | 1980 | 18.578004584115 | 1979 | 18.550116333815 | 1978 | 18.777549741695 | 1977 | 17.999293204145 | 1976 | 17.862332320585 | 1975 | 18.010925405414 | 1974 | 18.397341031586 | 1973 | 18.196951020635 | 1972 | 17.888785496789 |
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