Year	Years
1990	73.9
1991	73.9
1992	73.9
1993	74
1994	74.1
1995	74.3
1996	74.5
1997	74.7
1998	75
1999	75.3
2000	75.5
2001	75.9
2002	76.3
2003	76.8
2004	77.1
2005	77.3
2006	77.4
2007	77.5
2008	77.8
2009	78.1
2010	78.5
2011	78.7
2012	78.7
2013	78.7