Year | Value | 2023 | 1.81 | 2022 | 1.82 | 2021 | 1.98 | 2020 | 1.976 | 2019 | 2.021 | 2018 | 2.093 | 2017 | 2.136 | 2016 | 2.228 | 2015 | 2.214 | 2014 | 2.18 | 2013 | 1.993 | 2012 | 1.929 | 2011 | 1.915 | 2010 | 1.973 | 2009 | 1.993 | 2008 | 1.832 | 2007 | 1.697 | 2006 | 1.617 | 2005 | 1.583 | 2004 | 1.566 | 2003 | 1.552 | 2002 | 1.571 | 2001 | 1.579 | 2000 | 1.609 | 1999 | 1.643 | 1998 | 1.703 | 1997 | 1.728 | 1996 | 1.759 | 1995 | 1.807 | 1994 | 1.835 | 1993 | 1.912 | 1992 | 2.045 | 1991 | 2.208 | 1990 | 2.306 | 1989 | 2.322 | 1988 | 2.318 | 1987 | 2.319 | 1986 | 2.38 | 1985 | 2.399 | 1984 | 2.378 | 1983 | 2.339 | 1982 | 2.312 | 1981 | 2.33 | 1980 | 2.347 | 1979 | 2.382 | 1978 | 2.417 | 1977 | 2.441 | 1976 | 2.51 | 1975 | 2.552 |
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