| Year | Value | | 2023 | 0.045865188719255 | | 2022 | 0.011148545485696 | | 2021 | 0.11975827471478 | | 2020 | 0.16654079456625 | | 2019 | 0.20460985169242 | | 2018 | 0.30292945248985 | | 2017 | 0.42296351013395 | | 2016 | 0.45126606279719 | | 2015 | 0.46097629405941 | | 2014 | 0.53012986413719 | | 2013 | 0.58732569868065 | | 2012 | 0.61959134675136 | | 2011 | 0.62180794825387 | | 2010 | 0.67061733834359 | | 2009 | 0.73854268159594 | | 2008 | 0.76815617938942 | | 2007 | 0.80004418054119 | | 2006 | 0.83006330336846 | | 2005 | 0.86008789446185 | | 2004 | 0.89607727530391 | | 2003 | 0.93194750463353 | | 2002 | 0.96202688490736 | | 2001 | 1.0158484684114 | | 2000 | 1.1312701797585 | | 1999 | 1.2540989911009 | | 1998 | 1.305645029973 | | 1997 | 1.3337217009805 | | 1996 | 1.3810398732234 | | 1995 | 1.4270598715355 | | 1994 | 1.4743294424554 | | 1993 | 1.5436271168731 | | 1992 | 1.5894596167319 | | 1991 | 1.629207106788 | | 1990 | 1.6381160795275 | | 1989 | 1.6464946537895 | | 1988 | 1.7050269440477 | | 1987 | 1.7361291632613 | | 1986 | 1.7883051911759 | | 1985 | 1.845108149543 | | 1984 | 1.8991086505665 | | 1983 | 1.9365752602161 | | 1982 | 1.9533262294754 | | 1981 | 2.0078184838506 | | 1980 | 2.0618278623957 | | 1979 | 2.1003714139049 | | 1978 | 2.1817091156135 | | 1977 | 2.2362618356555 | | 1976 | 2.3094684329794 | | 1975 | 2.4406667312231 | | 1974 | 2.5479080779531 |
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