# year    value 
 1980 10.79491 
 1981 11.00368 
 1982 10.61803 
 1983 10.29372 
 1984 10.73134 
 1985  10.7913 
 1986 10.93746 
 1987 10.87491 
 1988 10.95094 
 1989 11.13145 
 1990 11.00667 
 1991 11.19444 
 1992 10.37203 
 1993 10.56947 
 1994 11.10751 
 1995 11.05097 
 1996 11.12253 
 1997 11.21818 
 1998 11.51406 
 1999  11.3375 
 2000 11.58918 
 2001 11.47519 
 2002 11.52414 
 2003 11.71214 
 2004 11.62163 
 2005 11.54369