Year Years 1990 69.7 1991 69.7 1992 69.7 1993 69.7 1994 69.6 1995 69.6 1996 69.6 1997 69.6 1998 69.6 1999 69.7 2000 69.8 2001 70 2002 70.1 2003 70.3 2004 70.5 2005 70.7 2006 70.9 2007 71.2 2008 71.6 2009 72.1 2010 72.3 2011 72.4 2012 72.6 2013 72.7