# year    value 
 1980 -0.2693161 
 1981 -0.3028121 
 1982 -0.4162134 
 1983 -0.6123722 
 1984 -0.4010514 
 1985 -0.5146142 
 1986 -0.3815559 
 1987 -0.2650947 
 1988 -0.2369259 
 1989 -0.2533013 
 1990 -0.1997027 
 1991 -0.2057465 
 1992 -0.544425 
 1993 -0.4270652 
 1994 -0.404366 
 1995 -0.4328252 
 1996 -0.1911487 
 1997 -0.1508642 
 1998 -0.142272 
 1999 -0.03732996 
 2000 -0.09026536 
 2001 0.05840407 
 2002 0.1607882 
 2003 -0.0304565 
 2004 -0.09546171 
 2005 0.0426297