| Year | Value | | 2023 | 176.14642303433 | | 2022 | 168.34848283499 | | 2021 | 153.37094130675 | | 2020 | 146.36310077519 | | 2019 | 143.82104097453 | | 2018 | 139.96214839424 | | 2017 | 134.61055740125 | | 2016 | 129.92986341824 | | 2015 | 124.82834994463 | | 2014 | 121.04097452935 | | 2013 | 115.24547803618 | | 2012 | 112.23329641934 | | 2011 | 108.25396825397 | | 2010 | 100 | | 2009 | 95.555555555556 | | 2008 | 93.141380583241 | | 2007 | 84.55500219996 | | 2006 | 78.197199118504 | | 2005 | 71.354743447767 | | 2004 | 66.806939830196 | | 2003 | 64.038390550018 | | 2002 | 56.057585825028 | | 2001 | 50.726145167228 | | 2000 | 47.289141830339 | | 1999 | 43.391635778942 | | 1998 | 40.647039600481 | | 1997 | 36.437336324173 | | 1996 | 34.069643905892 | | 1995 | 31.028909058717 | | 1994 | 27.356222794096 | | 1993 | 22.689795287092 | | 1992 | 19.194697761603 | | 1991 | 16.663113608006 | | 1990 | 13.413617530254 | | 1989 | 9.7724186307268 | | 1988 | 7.7299906938725 | | 1987 | 6.3053448601722 | | 1986 | 5.1763653847092 | | 1985 | 3.9291508533163 | | 1984 | 3.1380308053172 | | 1983 | 2.6082558876023 | | 1982 | 2.2993648360254 | | 1981 | 2.187370057718 | | 1980 | 1.9361592522098 | | 1979 | 1.5812180225211 | | 1978 | 1.2337743512099 | | 1977 | 1.1149210109745 | | 1976 | 1.0194975406784 | | 1975 | 0.97583278306477 | | 1974 | 0.91461692288096 |
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