# year    value 
 1980 -5.98771 
 1981 -5.887188 
 1982 -5.892447 
 1983 -6.216211 
 1984 -6.100028 
 1985 -6.06597 
 1986 -6.015366 
 1987 -5.891641 
 1988 -5.821685 
 1989 -5.852087 
 1990 -5.700347 
 1991 -5.680387 
 1992 -6.034827 
 1993  -5.9733 
 1994 -5.944097 
 1995 -5.875429 
 1996 -5.72564 
 1997 -5.698005 
 1998 -5.563222 
 1999 -5.625099 
 2000  -5.5168 
 2001 -5.435566 
 2002 -5.338197 
 2003 -5.262258 
 2004 -5.316644 
 2005 -5.236373