# year    value 
 1980 -0.4313749 
 1981 -0.4264807 
 1982 -0.4268672 
 1983 -0.7115973 
 1984 -0.4889672 
 1985 -0.5190132 
 1986 -0.4668361 
 1987 -0.409196 
 1988 -0.3155054 
 1989 -0.2112388 
 1990 -0.20372 
 1991 -0.1989597 
 1992 -0.6147821 
 1993 -0.5522507 
 1994 -0.3874511 
 1995 -0.3500206 
 1996 -0.2039381 
 1997 -0.1437697 
 1998 -0.05798641 
 1999 -0.1059626 
 2000 0.08166078 
 2001 0.1303138 
 2002 0.1148808 
 2003 0.112344 
 2004 0.1585548 
 2005 0.1799788