Year | Value | 2022 | 1.4086617891857 | 2021 | 1.0092594948764 | 2020 | 1.1747583077734 | 2019 | 1.6224615282717 | 2018 | 1.7911195662436 | 2017 | 2.0795647059945 | 2016 | 2.3258972456134 | 2015 | 2.4681785576309 | 2014 | 2.415386779254 | 2013 | 2.2033890817754 | 2012 | 2.0107106305061 | 2011 | 1.9081612380098 | 2010 | 2.1230340273596 | 2009 | 2.5159804166867 | 2008 | 2.7435404272287 | 2007 | 2.7558027103446 | 2006 | 2.4939317875825 | 2005 | 2.0179830740629 | 2004 | 1.7553141005914 | 2003 | 1.7201352714929 | 2002 | 1.7604243350611 | 2001 | 1.8001137980457 | 2000 | 1.8838891265665 | 1999 | 1.9149417944161 | 1998 | 1.8600489274415 | 1997 | 1.8497951039715 | 1996 | 1.8113361293624 | 1995 | 1.6910772159473 | 1994 | 1.8020202315502 | 1993 | 1.6765209895489 | 1992 | 1.810542213657 | 1991 | 2.4356331765116 | 1990 | 2.6660786443183 | 1989 | 2.670156249852 | 1988 | 2.471821672113 | 1987 | 2.4735572961872 | 1986 | 2.4946874844307 | 1985 | 2.4651907179426 | 1984 | 2.397417271303 | 1983 | 2.3987905733886 | 1982 | 2.3651078330144 | 1981 | 2.3482290517821 | 1980 | 2.4166332053467 | 1979 | 2.4953501448048 | 1978 | 2.634489940369 | 1977 | 2.7007123078623 | 1976 | 2.6435669522733 | 1975 | 2.5445967794337 | 1974 | 2.3739326050209 | 1973 | 2.2796170901626 | 1972 | 2.1628777783664 | 1971 | 2.0551216425436 | 1970 | 1.9416104041347 | 1969 | 1.903253167992 | 1968 | 1.9357899111177 | 1967 | 1.8306394967904 | 1966 | 1.7516795591099 | 1965 | 1.7956184547049 | 1964 | 1.9526568854547 | 1963 | 2.0688262146981 | 1962 | 2.0695754378955 | 1961 | 1.8074235555875 |
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