Year	Years
1990	70.2
1991	70.6
1992	70.8
1993	71
1994	71.1
1995	71.1
1996	71
1997	70.9
1998	70.7
1999	70.6
2000	70.5
2001	70.3
2002	70.1
2003	70
2004	69.9
2005	70.1
2006	70.3
2007	70.6
2008	70.9
2009	71.2
2010	71.2
2011	71.3
2012	71.4
2013	71.5