# year    value 
 1980 -0.1190442 
 1981 -0.04709689 
 1982 -0.1974354 
 1983 -0.4040072 
 1984 -0.1988706 
 1985 -0.2575255 
 1986 -0.1671403 
 1987 -0.04741287 
 1988 -0.001472125 
 1989 -0.0286274 
 1990 0.04538247 
 1991 0.03764344 
 1992 -0.3666695 
 1993 -0.1665171 
 1994 -0.1933627 
 1995 -0.1607717 
 1996 0.08540188 
 1997 0.1149331 
 1998 0.09279235 
 1999 0.2384646 
 2000 0.1929418 
 2001 0.2977404 
 2002 0.3844963 
 2003 0.2799813 
 2004 0.2606941 
 2005 0.3739419