Year Years 1990 68.3 1991 68.7 1992 69 1993 69.3 1994 69.6 1995 69.7 1996 70.1 1997 70.4 1998 70.7 1999 71 2000 71.3 2001 71.5 2002 71.8 2003 72 2004 72.2 2005 72.5 2006 72.8 2007 73 2008 73.3 2009 73.5 2010 73.7 2011 73.9 2012 74.1 2013 74.3