# year    value 
 1980 -2.659571 
 1981 -2.687512 
 1982 -2.800182 
 1983 -2.939357 
 1984 -2.807749 
 1985 -2.776634 
 1986 -2.734077 
 1987 -2.683405 
 1988 -2.56388 
 1989 -2.582671 
 1990 -2.483951 
 1991 -2.630054 
 1992 -2.915887 
 1993 -2.722385 
 1994 -2.704999 
 1995 -2.671472 
 1996 -2.493164 
 1997 -2.477854 
 1998 -2.363765 
 1999 -2.385551 
 2000 -2.389029 
 2001 -2.280604 
 2002 -2.196383 
 2003 -2.271671 
 2004 -2.268477 
 2005 -2.241452