# year    value 
 1980 -11.56629 
 1981 -11.41651 
 1982 -11.4052 
 1983 -12.02194 
 1984 -11.56712 
 1985 -11.66113 
 1986 -11.49099 
 1987 -11.50561 
 1988 -11.32936 
 1989 -11.49242 
 1990 -11.26077 
 1991 -11.13133 
 1992 -11.69667 
 1993 -11.65588 
 1994 -11.65228 
 1995 -11.20095 
 1996 -11.06195 
 1997 -11.24192 
 1998 -11.28696 
 1999 -11.23985 
 2000 -10.86202 
 2001 -10.94562 
 2002 -10.8854 
 2003 -10.81022 
 2004 -10.89925 
 2005 -10.90751