Year | Value | 2009 | 20.696450254262 | 2008 | 23.52698137466 | 2007 | 25.319069281742 | 2006 | 26.214205063197 | 2005 | 26.60448466758 | 2004 | 38.903757473211 | 2003 | 34.231534143703 | 2002 | 33.658561393969 | 2001 | 28.017417562748 | 2000 | 22.057928024748 | 1999 | 14.676049686589 | 1998 | 14.763431712584 | 1997 | 13.375202089292 | 1996 | 13.509237284192 | 1995 | 9.8387359504805 | 1994 | 18.647675180092 | 1993 | 22.333414693678 | 1992 | 22.740601427734 | 1991 | 26.552410838211 | 1990 | 23.371285491567 | 1989 | 23.811803323531 | 1988 | 12.157620567972 | 1987 | 17.089693020065 | 1986 | 20.701722073856 | 1985 | 22.991283334772 | 1984 | 35.427083333333 | 1983 | 41.433778857837 | 1982 | 34.380952380952 | 1981 | 30.251202565473 | 1980 | 45.933562428408 | 1979 | 26.060764798324 | 1978 | 29.245283018868 | 1977 | 35.40864356012 | 1976 | 32.947658402204 | 1975 | 30.567081604426 | 1974 | 36.621382161843 | 1973 | 43.039772727273 | 1972 | 42.551210428305 |
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