# year    value 
 1980 -0.3607754 
 1981 -0.232531 
 1982 -0.392179 
 1983 -0.6543172 
 1984 -0.4592416 
 1985 -0.4133266 
 1986 -0.360372 
 1987 -0.2758192 
 1988 -0.2156994 
 1989 -0.108165 
 1990 -0.05804435 
 1991 -0.07881048 
 1992 -0.5631784 
 1993 -0.4093808 
 1994 -0.1594759 
 1995 -0.08226661 
 1996 -0.07458044 
 1997 0.06676061 
 1998 0.09040655 
 1999 0.122115 
 2000 0.2613786 
 2001 0.2812758 
 2002 0.3274159 
 2003 0.4092499 
 2004 0.3865188 
 2005 1.379735