# year    value 
 1980 11.59252 
 1981 12.28644 
 1982 13.30089 
 1983 11.77053 
 1984 12.44449 
 1985 11.76966 
 1986 12.35789 
 1987 13.55614 
 1988 11.58918 
 1989 11.79456 
 1990 12.32578 
 1991 12.25639 
 1992 12.42371 
 1993 11.14852 
 1994 13.09512 
 1995 12.02582 
 1996 11.62446 
 1997 12.39517 
 1998 11.47827 
 1999  12.6627 
 2000 13.58176 
 2001 12.13676 
 2002 12.92205 
 2003 12.20906 
 2004 13.11184 
 2005 12.66202 
 2006 14.41131 
 2007   11.277 
 2008 12.47664 
 2009 13.47042 
 2010 11.97119 
 2011 13.14747 
 2012 13.44381 
 2013 13.16196 
 2014 14.16167 
 2015 12.93706 
 2016 12.99887 
 2017 12.46583 
 2018 14.05123