# year    value 
 1980 -0.484896 
 1981 -0.2494805 
 1982 -0.366661 
 1983 -0.6380036 
 1984 -0.5250296 
 1985 -0.4722028 
 1986 -0.3040594 
 1987 -0.2730776 
 1988 -0.1789066 
 1989 -0.0617845 
 1990 0.001205135 
 1991 -0.2853589 
 1992 -0.4067086 
 1993 -0.5017011 
 1994 -0.2335667 
 1995 -0.02928031 
 1996 -0.06165421 
 1997 0.06606668 
 1998 0.07241581 
 1999 0.1111211 
 2000 0.308713 
 2001 0.3614679 
 2002 0.2712667 
 2003 0.464251 
 2004 0.3377326 
 2005 0.948745