Year Years 1990 70.8 1991 70.7 1992 71.1 1993 71.7 1994 71.8 1995 72 1996 72.4 1997 72.7 1998 73 1999 73.2 2000 73.8 2001 74.3 2002 74.6 2003 74.9 2004 75 2005 75 2006 75 2007 75.1 2008 75.3 2009 75.6 2010 76.1 2011 76.5 2012 76.7 2013 76.9