Year Years 1990 70.3 1991 70.6 1992 70.9 1993 71.3 1994 71.9 1995 72.2 1996 72.5 1997 72.9 1998 73.3 1999 73.6 2000 73.5 2001 73.6 2002 73.5 2003 73.7 2004 73.6 2005 73.7 2006 73.3 2007 73.7 2008 73.5 2009 73.6 2010 74 2011 74.1 2012 74.3 2013 74.6