Year	Years
1990	69.9
1991	69.4
1992	68.8
1993	68
1994	67.3
1995	66.8
1996	66.8
1997	67.1
1998	67.5
1999	67.6
2000	67.5
2001	67.5
2002	67.4
2003	67.4
2004	67.3
2005	67.2
2006	67.3
2007	67.6
2008	68.2
2009	69.3
2010	70.4
2011	71.2
2012	71.5
2013	71.7