Year | Value | 2022 | 29.110954149897 | 2021 | 30.836994346152 | 2020 | 29.031497466695 | 2019 | 30.087281919587 | 2018 | 29.878431742983 | 2017 | 28.839017924296 | 2016 | 28.603994946208 | 2015 | 28.31064498434 | 2014 | 27.574904363389 | 2013 | 26.582385466817 | 2012 | 26.800263607893 | 2011 | 27.822586882659 | 2010 | 25.776368507765 | 2009 | 24.396838769595 | 2008 | 27.148700022265 | 2007 | 28.267438095519 | 2006 | 26.338421875859 | 2005 | 24.130960154079 | 2004 | 24.320947270901 | 2003 | 21.796395428577 | 2002 | 22.639589649841 | 2001 | 22.540647689815 | 2000 | 22.668917917017 | 1999 | 22.563416009634 | 1998 | 23.226001372924 | 1997 | 22.785680667803 | 1996 | 22.521541031625 | 1995 | 23.038072905414 | 1994 | 22.7480572071 | 1993 | 22.513156844832 | 1992 | 23.509816965586 | 1991 | 23.716941789458 | 1990 | 24.402556239464 | 1989 | 23.153427339432 | 1988 | 22.147421191274 | 1987 | 20.973779950276 | 1986 | 21.808018863 | 1985 | 20.29797376555 | 1984 | 19.501025853804 | 1983 | 18.883641113763 | 1982 | 18.316911775917 | 1981 | 18.005572928017 | 1980 | 19.375059950394 | 1979 | 20.596941387802 | 1978 | 21.144669345565 | 1977 | 20.246881651176 | 1976 | 20.538169149077 | 1975 | 20.020196002291 | 1974 | 23.541984772398 | 1973 | 24.70176697166 | 1972 | 24.979120642962 | 1971 | 26.143315778753 |
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