# year    value 
 1980 -0.1678585 
 1981 -0.1811676 
 1982 -0.3048083 
 1983 -0.4108371 
 1984 -0.2748815 
 1985 -0.3131648 
 1986 -0.2567827 
 1987 -0.1426128 
 1988 -0.07639804 
 1989 -0.06786762 
 1990 0.003369608 
 1991 -0.1815359 
 1992 -0.3705773 
 1993 -0.2519043 
 1994 -0.2414267 
 1995 -0.156375 
 1996 -0.001074148 
 1997 0.04653357 
 1998 0.08787821 
 1999 0.1147066 
 2000 0.1352877 
 2001 0.2462246 
 2002 0.2998062 
 2003 0.2155895 
 2004 0.262157 
 2005 0.1905975