# year    value 
 1980 11.48286 
 1981 11.57913 
 1982 11.34388 
 1983 11.06459 
 1984 11.39877 
 1985 11.50267 
 1986 11.51681 
 1987 11.55372 
 1988 11.61942 
 1989 11.73833 
 1990 11.67509 
 1991 11.75393 
 1992  11.1257 
 1993 11.38614 
 1994 11.68919 
 1995 11.72624 
 1996 11.76196 
 1997  11.9147 
 1998 12.00231 
 1999 11.95662 
 2000 12.11642 
 2001 12.13647 
 2002 12.14013 
 2003 12.19178 
 2004 12.18132 
 2005 12.20191