Year | Value | 2022 | 50.496108607771 | 2021 | 50.528952282027 | 2020 | 50.561102551348 | 2019 | 50.589222782877 | 2018 | 50.613391677749 | 2017 | 50.635957063692 | 2016 | 50.657228749192 | 2015 | 50.68384246104 | 2014 | 50.719374652396 | 2013 | 50.750553206641 | 2012 | 50.775894936519 | 2011 | 50.801449684215 | 2010 | 50.814850852461 | 2009 | 50.816190238552 | 2008 | 50.817261491025 | 2007 | 50.81678339834 | 2006 | 50.80321977626 | 2005 | 50.768972717081 | 2004 | 50.720199744941 | 2003 | 50.665101172768 | 2002 | 50.646909476311 | 2001 | 50.673397080407 | 2000 | 50.706889711663 | 1999 | 50.741384087677 | 1998 | 50.775785496515 | 1997 | 50.810683705275 | 1996 | 50.846402156888 | 1995 | 50.877908013495 | 1994 | 50.906322766763 | 1993 | 50.924766167694 | 1992 | 50.944328722137 | 1991 | 50.979844538666 | 1990 | 51.030347927359 | 1989 | 51.084361753593 | 1988 | 51.146523859018 | 1987 | 51.231960118311 | 1986 | 51.326081731209 | 1985 | 51.413895268835 | 1984 | 51.492684315352 | 1983 | 51.591287868584 | 1982 | 51.715154083421 | 1981 | 51.638861020009 | 1980 | 51.511162943609 | 1979 | 51.548741563402 | 1978 | 51.565824326678 | 1977 | 51.570815727279 | 1976 | 51.577155089114 | 1975 | 51.566976218384 | 1974 | 51.551399014044 | 1973 | 51.553135963458 | 1972 | 51.551566185149 | 1971 | 51.547847653739 | 1970 | 51.546021303209 | 1969 | 51.54411577183 | 1968 | 51.537590163638 | 1967 | 51.521812691305 | 1966 | 51.498966482537 | 1965 | 51.471462348157 | 1964 | 51.441151692055 | 1963 | 51.412135829538 | 1962 | 51.381244456438 | 1961 | 51.347908001693 | 1960 | 51.314332366192 |
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