# year    value 
 1980 1.495429 
 1981 1.533467 
 1982 1.466066 
 1983 1.260988 
 1984  1.40753 
 1985 1.416035 
 1986 1.370158 
 1987 1.487472 
 1988 1.611382 
 1989 1.527596 
 1990 1.653998 
 1991 1.681745 
 1992    1.314 
 1993 1.431515 
 1994 1.388452 
 1995 1.432148 
 1996 1.620695 
 1997 1.687158 
 1998  1.74811 
 1999  1.72046 
 2000 1.742902 
 2001 1.790676 
 2002 1.949931 
 2003 1.851934 
 2004 1.838852 
 2005 1.932359