| Year | Value | | 2022 | 0.99535137722118 | | 2021 | 1.1097830684621 | | 2020 | 1.2419702846472 | | 2019 | 1.1700444452059 | | 2018 | 1.2308760693725 | | 2017 | 1.222845474521 | | 2016 | 1.2018590229935 | | 2015 | 1.2158989479119 | | 2014 | 1.2508727381082 | | 2013 | 1.2617723590541 | | 2012 | 1.2696865490081 | | 2011 | 1.2522843314443 | | 2010 | 1.3500663813971 | | 2009 | 1.3785131902509 | | 2008 | 1.1879411234234 | | 2007 | 1.1415523338745 | | 2006 | 1.0719907137474 | | 2005 | 1.1068874849741 | | 2004 | 1.0469775710685 | | 2003 | 1.0751488440511 | | 2002 | 1.1674417412645 | | 2001 | 1.2273711463099 | | 2000 | 1.1862057445151 | | 1999 | 1.2312065586632 | | 1998 | 1.3245834283188 | | 1997 | 1.2808763327688 | | 1996 | 1.4677890717919 | | 1995 | 1.5309526232878 | | 1994 | 1.3966438416461 | | 1993 | 1.294191109593 | | 1992 | 1.2315237796105 | | 1991 | 1.4068639118901 | | 1990 | 1.6792084004561 | | 1989 | 1.957606902676 | | 1988 | 1.4299609662362 | | 1987 | 1.6849064850903 | | 1986 | 1.6712174126737 | | 1985 | 1.5184496216309 | | 1984 | 1.5651072814448 | | 1983 | 1.7269269531966 | | 1982 | 1.1961996725879 | | 1981 | 0.89704298778799 | | 1980 | 0.82810458535458 | | 1979 | 0.96323054203408 | | 1978 | 0.98506371414297 | | 1977 | 1.0637227985186 | | 1976 | 0.96432982739121 | | 1975 | 0.94945171058211 | | 1974 | 0.8952934958955 | | 1973 | 0.88576465532252 | | 1972 | 0.94379463257361 | | 1971 | 1.0871677038114 | | 1970 | 0.97849891213549 | | 1969 | 1.0290099809522 | | 1968 | 1.0318452443179 | | 1967 | 1.15258496949 | | 1966 | 1.195051399848 | | 1965 | 1.3008137442083 | | 1964 | 1.3726245786169 | | 1963 | 1.4428908356683 | | 1962 | 1.4138090220774 | | 1961 | 1.2224185205732 | | 1960 | 1.2464143785283 |
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