# year    value 
 1980 -0.2786918 
 1981 -0.2138307 
 1982 -0.3474031 
 1983 -0.5999801 
 1984 -0.3642318 
 1985 -0.3080992 
 1986 -0.2731476 
 1987 -0.2613291 
 1988 -0.1076192 
 1989 -0.0970328 
 1990 -0.08414423 
 1991 -0.09246849 
 1992 -0.5552886 
 1993 -0.3915872 
 1994 -0.2005932 
 1995 -0.07999705 
 1996 0.03638629 
 1997 0.04574505 
 1998 0.08822604 
 1999 0.1106964 
 2000 0.2250351 
 2001 0.2689203 
 2002 0.3327533 
 2003 0.2933466 
 2004 0.3654275 
 2005 1.348256