| Year | Value | | 2022 | 0.10488995063888 | | 2021 | 0.37963660702723 | | 2020 | 0.068656249468097 | | 2019 | 0.17156574022387 | | 2018 | 0.039036546348961 | | 2017 | 0.013386074666263 | | 2016 | 0.059816599104739 | | 2015 | 0.15748140517601 | | 2014 | 0.046953900254922 | | 2013 | 0.30097214140619 | | 2012 | 0.73656551881404 | | 2011 | 0.80216403969433 | | 2010 | 0.72947525693253 | | 2009 | 0.88818504275025 | | 2008 | 0.30379052934121 | | 2007 | 0.52164673444726 | | 2006 | 0.56848471240371 | | 2005 | 0.63529221845948 | | 2004 | 0.61926241002473 | | 2003 | 0.67536580586597 | | 2002 | 0.89725367267161 | | 2001 | -1.5512383969893 | | 2000 | -1.9446291567975 | | 1999 | -2.0573768786356 | | 1998 | -2.474222975613 | | 1997 | -3.2075181716222 | | 1996 | -3.6295460797213 | | 1995 | -3.7577160682364 | | 1994 | -1.5394301205047 | | 1993 | 0.76855845063073 | | 1992 | 0.77451105028642 | | 1991 | 0.70347564932021 | | 1990 | 0.027068389492002 | | 1989 | 0.26266431611875 | | 1988 | 0.99012786819994 | | 1987 | 0.82557623861112 | | 1986 | 0.88819252898584 | | 1985 | 0.87667899476913 | | 1984 | 0.85387967069117 | | 1983 | 0.87884234848677 | | 1982 | 0.84666649259966 | | 1981 | 0.82031622927505 | | 1980 | 0.84290050517833 | | 1979 | 0.73630527828658 | | 1978 | 0.58382341021636 | | 1977 | 0.68162522213816 | | 1976 | 0.72109030212631 | | 1975 | 0.73801072976225 | | 1974 | 0.8683462213283 | | 1973 | 0.88070836076438 | | 1972 | 1.0109666305762 | | 1971 | 1.040707699063 | | 1970 | 0.96583760975283 | | 1969 | 0.93566782146393 | | 1968 | 0.90705260250457 | | 1967 | 0.98087961095848 | | 1966 | 1.1434780983699 | | 1965 | 1.3167710374648 | | 1964 | 1.4103064723647 | | 1963 | 1.4730217240403 | | 1962 | 1.5193421861259 | | 1961 | 1.5784358624219 |
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