# year    value 
 1980 9.933713 
 1981 9.982495 
 1982 9.785229 
 1983 9.590977 
 1984 9.753532 
 1985 9.811719 
 1986 9.816764 
 1987  9.90816 
 1988  10.0104 
 1989  10.0767 
 1990 10.12259 
 1991 10.09165 
 1992 9.601318 
 1993 9.827022 
 1994 9.879515 
 1995 10.00149 
 1996 10.09357 
 1997 10.19179 
 1998 10.29467 
 1999 10.27706 
 2000  10.3132 
 2001  10.4101 
 2002 10.43699 
 2003 10.41503 
 2004 10.41467 
 2005 10.49995