Year | Value | 2022 | 1.4398684949477 | 2021 | 1.4803168061015 | 2020 | 1.519987853578 | 2019 | 1.5603860478109 | 2018 | 1.6003859815037 | 2017 | 1.6276537997384 | 2016 | 1.6580733183424 | 2015 | 1.6914650930239 | 2014 | 1.7287576027797 | 2013 | 1.7571676981292 | 2012 | 1.7774957867315 | 2011 | 1.8194877560567 | 2010 | 1.83655642844 | 2009 | 1.8810634381898 | 2008 | 1.9274476375289 | 2007 | 1.975962167134 | 2006 | 2.0262280968057 | 2005 | 2.0771706306636 | 2004 | 2.1259859710274 | 2003 | 2.1807452455045 | 2002 | 2.2978824165046 | 2001 | 2.4024009004308 | 2000 | 2.4339436446375 | 1999 | 2.3694764118509 | 1998 | 2.3619874831718 | 1997 | 2.3580592328023 | 1996 | 2.4027209211898 | 1995 | 2.4529887926022 | 1994 | 2.4905588724221 | 1993 | 2.5506234765169 | 1992 | 2.6246686742016 | 1991 | 2.6894296006475 | 1990 | 2.7344725274704 | 1989 | 2.7593219952698 | 1988 | 2.7682469055324 | 1987 | 2.7685642460267 | 1986 | 2.7631706257542 | 1985 | 2.7540948392461 | 1984 | 2.7396884481815 | 1983 | 2.7155991403425 | 1982 | 2.6717660634518 | 1981 | 2.5906915429144 | 1980 | 2.4946543543789 | 1979 | 2.3891667262631 | 1978 | 2.3007837622334 | 1977 | 2.2501609725378 | 1976 | 2.2391145905205 | 1975 | 2.2573479720125 | 1974 | 2.2921223116154 | 1973 | 2.3262037192253 | 1972 | 2.3724648585552 | 1971 | 2.4332376507953 | 1970 | 2.5076632120774 | 1969 | 2.5896815670028 | 1968 | 2.6715091039617 | 1967 | 2.7445368465347 | 1966 | 2.8044201852642 | 1965 | 2.850493537305 | 1964 | 2.8933604870594 | 1963 | 2.9222130773407 | 1962 | 2.9361423190484 | 1961 | 2.9362345179632 |
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