Year | Value | 2022 | 49.675154563554 | 2021 | 49.641127282536 | 2020 | 49.585477837985 | 2019 | 49.531502040042 | 2018 | 49.497859827601 | 2017 | 49.465024969455 | 2016 | 49.433903983463 | 2015 | 49.400516734334 | 2014 | 49.366431304203 | 2013 | 49.336142804123 | 2012 | 49.305856050772 | 2011 | 49.2752748281 | 2010 | 49.248961523301 | 2009 | 49.228338801799 | 2008 | 49.219001365913 | 2007 | 49.214932964318 | 2006 | 49.21572794899 | 2005 | 49.227634859819 | 2004 | 49.242701397527 | 2003 | 49.261560118738 | 2002 | 49.282432041731 | 2001 | 49.307842797355 | 2000 | 49.314555397408 | 1999 | 49.213043341014 | 1998 | 49.020510754236 | 1997 | 48.825892567874 | 1996 | 48.621117686078 | 1995 | 48.399003291271 | 1994 | 48.174076554182 | 1993 | 47.950062181791 | 1992 | 47.724082054577 | 1991 | 47.494297955791 | 1990 | 47.294648604471 | 1989 | 47.225598302875 | 1988 | 47.272672623028 | 1987 | 47.347208254324 | 1986 | 47.437667697039 | 1985 | 47.536394626028 | 1984 | 47.639988513763 | 1983 | 47.758824863312 | 1982 | 47.89696098598 | 1981 | 48.043207532172 | 1980 | 48.134849391582 | 1979 | 47.968271639299 | 1978 | 47.618011541008 | 1977 | 47.279023110459 | 1976 | 46.923909833645 | 1975 | 46.56205392147 | 1974 | 46.195892282876 | 1973 | 45.815983175605 | 1972 | 45.423692291117 | 1971 | 45.026241644108 | 1970 | 44.605889014723 | 1969 | 44.112140892597 | 1968 | 43.559955788632 | 1967 | 42.993531384763 | 1966 | 42.417469680871 | 1965 | 41.834153635287 | 1964 | 41.235802139377 | 1963 | 40.631980882124 | 1962 | 40.016177796637 | 1961 | 39.386514694137 | 1960 | 38.751485340039 |
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