Year | Value | 2000 | 37.93825045807 | 1999 | 36.782317322467 | 1998 | 29.406719214346 | 1997 | 36.135149177245 | 1996 | 40.174633854082 | 1995 | 35.202589851945 | 1994 | 35.487105471141 | 1993 | 35.72323212989 | 1990 | 23.238938040816 | 1989 | 18.493966370215 | 1980 | 22.223264131027 | 1979 | 28.707863784076 | 1978 | 24.957224137161 | 1977 | 36.287357059818 | 1976 | 39.982654951523 |
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