# year    value 
 1980 -0.2708663 
 1981 -0.167845 
 1982 -0.3088553 
 1983 -0.5555845 
 1984 -0.3343108 
 1985 -0.3231105 
 1986 -0.2692887 
 1987 -0.2175175 
 1988 -0.1280065 
 1989 -0.05774483 
 1990 -0.04145636 
 1991 -0.07534849 
 1992 -0.5548043 
 1993 -0.3627283 
 1994 -0.233469 
 1995 -0.1022918 
 1996 0.03438121 
 1997 0.0322498 
 1998 0.08769875 
 1999 0.1143368 
 2000 0.2173417 
 2001 0.2516907 
 2002 0.2823705 
 2003 0.3261298 
 2004 0.3332354 
 2005 1.351174