Year | Value | 2021 | 10.510229784648 | 2020 | 11.250522653802 | 2019 | 12.593831377144 | 2018 | 12.969554927265 | 2017 | 14.263758255897 | 2016 | 15.00486162349 | 2015 | 14.039804308894 | 2014 | 15.411320125024 | 2013 | 14.965684150404 | 2012 | 16.12304228523 | 2011 | 15.263751406448 | 2010 | 14.344849074782 | 2009 | 14.451595934779 | 2008 | 14.643763135023 | 2007 | 14.654968231148 | 2006 | 14.633971133268 | 2005 | 14.879453486212 | 2004 | 14.847546276151 | 2003 | 14.998709392574 | 2002 | 15.397983496235 | 2001 | 15.837044009211 | 2000 | 16.354714443654 | 1999 | 16.891337174388 | 1998 | 17.771356419358 | 1997 | 18.621686085215 | 1996 | 19.05287365409 | 1995 | 19.297942935366 | 1994 | 19.877684041846 | 1993 | 20.317227362882 | 1992 | 20.593616104654 | 1991 | 21.768168348294 | 1990 | 22.827565140285 | 1989 | 23.345245211675 | 1988 | 24.068104620437 | 1987 | 24.901170226393 | 1986 | 24.408322978139 | 1985 | 23.634990390053 | 1984 | 23.077395655485 | 1983 | 23.444244049861 | 1982 | 25.094177401763 | 1981 | 24.179453875563 | 1980 | 22.302745280601 | 1979 | 22.048998530118 | 1978 | 22.394165103283 | 1977 | 22.923173915255 | 1976 | 23.762431296746 | 1975 | 26.211175462063 | 1974 | 27.705059069217 | 1973 | 30.261822958332 | 1972 | 31.766405191171 | 1971 | 32.545685725012 | 1970 | 34.751727097666 | 1969 | 35.393032613712 | 1968 | 36.638680897135 | 1967 | 35.561075490761 | 1966 | 36.555703108595 | 1965 | 38.861560618121 | 1964 | 39.952172459497 | 1963 | 43.239432866714 | 1962 | 38.597484799485 | 1961 | 24.29645793297 | 1960 | 26.525970748281 |
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