Year | Value | 2023 | 54.672 | 2022 | 54.489 | 2021 | 54.329 | 2020 | 54.194 | 2019 | 54.084 | 2018 | 53.998 | 2017 | 53.936 | 2016 | 53.9 | 2015 | 53.887 | 2014 | 53.9 | 2013 | 53.937 | 2012 | 53.974 | 2011 | 53.96 | 2010 | 53.829 | 2009 | 53.698 | 2008 | 53.567 | 2007 | 53.436 | 2006 | 53.305 | 2005 | 53.174 | 2004 | 53.043 | 2003 | 52.912 | 2002 | 52.78 | 2001 | 52.852 | 2000 | 53.004 | 1999 | 53.158 | 1998 | 53.311 | 1997 | 53.463 | 1996 | 53.616 | 1995 | 53.769 | 1994 | 53.922 | 1993 | 54.074 | 1992 | 54.227 | 1991 | 53.93 | 1990 | 53.217 | 1989 | 52.504 | 1988 | 51.79 | 1987 | 51.073 | 1986 | 50.357 | 1985 | 49.641 | 1984 | 48.926 | 1983 | 48.21 | 1982 | 47.495 | 1981 | 46.781 | 1980 | 46.07 | 1979 | 45.358 | 1978 | 44.649 | 1977 | 43.942 | 1976 | 43.339 | 1975 | 42.831 | 1974 | 42.325 |
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