# year    value 
 1980 -0.1312562 
 1981 -0.1842188 
 1982 -0.2878085 
 1983 -0.4022722 
 1984 -0.2650089 
 1985 -0.3393967 
 1986 -0.2631818 
 1987 -0.1163483 
 1988 -0.08612638 
 1989 -0.07329814 
 1990 0.00275523 
 1991 -0.1681361 
 1992 -0.3775768 
 1993 -0.2386667 
 1994 -0.2523803 
 1995 -0.180188 
 1996 0.0333493 
 1997 0.04834999 
 1998 0.1023069 
 1999 0.1405433 
 2000 0.1335613 
 2001 0.2585124 
 2002 0.3057675 
 2003 0.1798963 
 2004 0.2341582 
 2005 0.1331524