Year	Years
1990	75.2
1991	75.2
1992	75.3
1993	75.5
1994	75.6
1995	75.8
1996	76
1997	76.2
1998	76.4
1999	76.7
2000	76.9
2001	77.1
2002	77.2
2003	77.2
2004	77.2
2005	77.2
2006	77.2
2007	77.1
2008	77.1
2009	77.1
2010	77.2
2011	77.4
2012	77.6
2013	77.8