# year    value 
 1980 -11.64377 
 1981 -11.37697 
 1982 -11.50942 
 1983 -12.12831 
 1984 -11.57922 
 1985 -11.76695 
 1986 -11.67559 
 1987 -11.45458 
 1988 -11.47111 
 1989 -11.5396 
 1990 -11.2769 
 1991 -11.27106 
 1992 -11.92237 
 1993 -11.70469 
 1994 -11.83457 
 1995 -11.32227 
 1996 -11.23274 
 1997 -11.39687 
 1998 -11.40034 
 1999 -11.38859 
 2000 -10.98245 
 2001 -11.06436 
 2002 -11.01427 
 2003 -10.93884 
 2004 -10.95821 
 2005 -11.03708