# year    value 
 1980 -0.1642773 
 1981 0.05450867 
 1982 0.0962173 
 1983 -0.5155108 
 1984 -0.2376185 
 1985 -0.1861802 
 1986 -0.1249151 
 1987 0.03077739 
 1988 0.2652558 
 1989 0.2045198 
 1990 0.08714643 
 1991 0.01195444 
 1992 -0.1938263 
 1993 -0.2851226 
 1994 0.1030216 
 1995 0.07259285 
 1996 0.2638041 
 1997 0.5576764 
 1998 0.3179732 
 1999 0.6508178 
 2000 0.5627586 
 2001 0.4641196 
 2002 0.7546254 
 2003 0.5712733 
 2004 0.4098142 
 2005 0.8047569