| Year | Value | | 2004 | 0.80827999791611 | | 2003 | 2.5789272927498 | | 2002 | 2.6682622804685 | | 2001 | 2.811413282185 | | 2000 | 4.1674266033168 | | 1999 | 5.297785042764 | | 1998 | 6.2454744837933 | | 1997 | 8.8588177025982 | | 1996 | 13.002725264285 | | 1995 | 15.265609774763 | | 1994 | 16.143610343962 | | 1993 | 18.204312477907 |
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