# year    value 
 1980 -0.08233307 
 1981 -0.02145688 
 1982 -0.1078969 
 1983 -0.3089736 
 1984 -0.1398673 
 1985 -0.157628 
 1986 -0.1400231 
 1987 -0.02842666 
 1988 0.07883783 
 1989 0.02558749 
 1990 0.09933239 
 1991 0.05493449 
 1992 -0.3175909 
 1993 -0.1219097 
 1994 -0.1082841 
 1995 -0.06630845 
 1996 0.09106568 
 1997 0.1588254 
 1998 0.1830571 
 1999 0.2268969 
 2000 0.2170073 
 2001 0.3221558 
 2002 0.4373283 
 2003 0.3343599 
 2004 0.3225723 
 2005 0.4425046