Year | Value | 2022 | 2.542089202954 | 2021 | 2.6043192827497 | 2020 | 2.6548591562052 | 2019 | 2.656010133459 | 2018 | 2.6733210207149 | 2017 | 2.7213314256453 | 2016 | 2.7160539722723 | 2015 | 2.6953931666389 | 2014 | 2.7054281126667 | 2013 | 2.749620706542 | 2012 | 2.8276562431883 | 2011 | 2.8502967783616 | 2010 | 2.8209818626083 | 2009 | 2.8035759348321 | 2008 | 2.838631601806 | 2007 | 2.8515438411641 | 2006 | 2.8267293229916 | 2005 | 2.8396229939129 | 2004 | 2.8724140266668 | 2003 | 2.9059077038532 | 2002 | 2.932969913141 | 2001 | 2.9212710592387 | 2000 | 2.9588051891924 | 1999 | 3.0281142940097 | 1998 | 3.060483959033 | 1997 | 3.1281590957008 | 1996 | 3.203571284763 | 1995 | 3.2830152556997 | 1994 | 3.3427982751408 | 1993 | 3.3652773438574 | 1992 | 4.0695064434744 | 1991 | 4.2113188342915 | 1990 | 3.5765414935268 | 1989 | 3.7143804497634 | 1988 | 3.7997099051442 | 1987 | 3.3135359540021 | 1986 | 2.8612810138349 | 1985 | 2.7252676698994 | 1984 | 2.4994251277615 | 1983 | 2.7087493924386 | 1982 | 3.8194599728375 | 1981 | 2.4685305709005 | 1980 | 0.53553788649059 | 1979 | 1.4482237842659 | 1978 | 1.6601208619824 | 1977 | 1.895887281236 | 1976 | 2.4786785697303 | 1975 | 2.3978345678174 | 1974 | 2.5548497542486 | 1973 | 2.6509085987612 | 1972 | 2.6844182693907 | 1971 | 2.7571081891371 | 1970 | 2.7862727527566 | 1969 | 2.768537250354 | 1968 | 2.7526007150339 | 1967 | 2.6210364734356 | 1966 | 2.5952441106254 | 1965 | 2.6796435130007 | 1964 | 2.629283764786 | 1963 | 2.5781399604814 | 1962 | 2.5280963127519 | 1961 | 2.4624049628787 |
|