| Year | Value | | 2004 | 1.0403076523747 | | 2003 | 2.6762203946207 | | 2002 | 2.750341782239 | | 2001 | 3.2043670558234 | | 2000 | 3.9685227926175 | | 1999 | 4.5917488038474 | | 1998 | 4.8165887468532 | | 1997 | 6.4899995423132 | | 1996 | 6.9356683880211 | | 1995 | 7.6282275512716 | | 1994 | 13.067349926794 | | 1988 | 4.1472252556339 | | 1987 | 5.4379274066281 | | 1986 | 4.8737249768178 | | 1985 | 4.1084888174966 | | 1984 | 4.0768296386274 |
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