Year | Value | 2021 | 2.4319812792512 | 2020 | 2.4319812792512 | 2019 | 2.4163806552262 | 2018 | 2.4110764430577 | 2017 | 2.4939157566303 | 2016 | 2.5745908028059 | 2015 | 2.657209664848 | 2014 | 2.5502727981294 | 2013 | 2.4349181605612 | 2012 | 2.3507404520655 | 2011 | 2.219797349961 | 2010 | 2.1356196414653 | 2009 | 2.0342946219797 | 2008 | 2.1621200311769 | 2007 | 2.2525331254871 | 2006 | 2.3335931410756 | 2005 | 2.4333593141076 | 2004 | 2.5237724084178 | 2003 | 2.614185502728 | 2002 | 2.6890101325019 | 2001 | 2.7950116913484 | 2000 | 2.8698363211224 | 1999 | 2.9961028838659 | 1998 | 3.0506625097428 | 1997 | 3.1254871395168 | 1996 | 3.2314886983632 | 1995 | 3.3219017926734 | 1994 | 3.4746687451286 | 1993 | 3.5650818394388 | 1992 | 3.655494933749 | 1991 | 3.7770849571317 | 1990 | 3.6299952236905 | 1989 | 3.4628243910205 | 1988 | 3.2797325266677 | 1987 | 3.1157459003343 | 1986 | 2.9995223690495 | 1985 | 2.9931539563764 | 1984 | 2.8339436395478 | 1983 | 2.7479700684604 | 1982 | 2.6428912593536 | 1981 | 2.5473650692565 | 1980 | 2.4518388791594 | 1979 | 2.4438783633179 | 1978 | 2.4199968157937 | 1977 | 2.3244706256965 | 1976 | 2.2130234039166 | 1975 | 2.1334182455023 | 1974 | 2.0219710237223 | 1973 | 2.0219710237223 | 1972 | 2.0219710237223 | 1971 | 1.9742079286738 | 1970 | 1.9662474128323 | 1969 | 1.9264448336252 | 1968 | 1.8946027702595 | 1967 | 2.0697341187709 | 1966 | 2.1015761821366 | 1965 | 2.1015761821366 | 1964 | 2.1174972138195 | 1963 | 2.1174972138195 | 1962 | 2.165260308868 | 1961 | 2.1174972138195 |
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