# year    value 
 1980 0.400054 
 1981 0.3519537 
 1982 0.5012761 
 1983 0.1022919 
 1984 0.3310377 
 1985 0.4081382 
 1986 0.3814107 
 1987 0.2912485 
 1988 0.5624275 
 1989 0.5754269 
 1990 0.5032303 
 1991 0.6767657 
 1992 0.04087682 
 1993 0.05708145 
 1994 0.441485 
 1995 0.507542 
 1996 0.7399086 
 1997 0.6494129 
 1998 0.7053269 
 1999 0.6397275 
 2000 0.8732355 
 2001 0.7734197 
 2002 1.002513 
 2003 0.8766193 
 2004 1.134355 
 2005 0.821582