# year    value 
 1980 -2.645306 
 1981 -2.669582 
 1982 -2.785465 
 1983 -2.921614 
 1984 -2.797756 
 1985 -2.750369 
 1986 -2.717605 
 1987  -2.6774 
 1988 -2.548012 
 1989 -2.566268 
 1990 -2.471316 
 1991 -2.609782 
 1992 -2.903312 
 1993 -2.703497 
 1994 -2.68158 
 1995  -2.6574 
 1996 -2.484162 
 1997 -2.465926 
 1998 -2.351723 
 1999 -2.37268 
 2000 -2.374367 
 2001 -2.27082 
 2002 -2.182275 
 2003 -2.255714 
 2004 -2.26457 
 2005 -2.23737