Year | Value | 2021 | 34.410532615201 | 2020 | 34.410532615201 | 2019 | 34.410532615201 | 2018 | 34.410532615201 | 2017 | 34.410532615201 | 2016 | 34.410532615201 | 2015 | 34.410532615201 | 2014 | 34.410532615201 | 2013 | 34.410532615201 | 2012 | 34.410532615201 | 2011 | 34.161180929583 | 2010 | 33.662477558348 | 2009 | 33.03137981082 | 2008 | 32.280666633302 | 2007 | 31.279715729943 | 2006 | 30.529002552425 | 2005 | 29.778289374906 | 2004 | 29.778289374906 | 2003 | 29.277813923227 | 2002 | 28.026625294029 | 2001 | 27.025674390671 | 2000 | 26.525198938992 | 1999 | 25.524248035634 | 1998 | 25.424152945298 | 1997 | 25.324057854962 | 1996 | 25.324057854962 | 1995 | 25.324057854962 | 1994 | 25.324057854962 | 1993 | 25.223962764626 | 1992 | 25.223962764626 | 1991 | 25.123867674291 | 1990 | 25.023772583955 | 1989 | 25.023772583955 | 1988 | 25.023772583955 | 1987 | 25.023772583955 | 1986 | 25.023772583955 | 1985 | 24.523297132276 | 1984 | 24.022821680597 | 1983 | 23.021870777238 | 1982 | 20.919873880186 | 1981 | 20.619588609179 | 1980 | 20.419398428507 | 1979 | 20.419398428507 | 1978 | 20.419398428507 | 1977 | 20.13412742105 | 1976 | 20.379360392373 | 1975 | 20.144136930084 | 1974 | 19.768780341324 | 1973 | 19.518542615485 | 1972 | 19.268304889645 | 1971 | 19.018067163806 | 1970 | 18.91797207347 | 1969 | 18.91797207347 | 1968 | 18.91797207347 | 1967 | 18.877934037335 | 1966 | 18.897953055403 | 1965 | 18.857915019268 | 1964 | 18.942995846054 | 1963 | 16.36054251539 | 1962 | 16.015214453731 | 1961 | 15.764976727892 |
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