Year	% net
1970	95.86356
1971	95.86924
1972	95.92679
1973	95.71176
1974	95.92917
1975	95.95885
1976	96.03519
1977	95.95106
1978	95.99923
1979	95.96558
1980	95.92576
1981	95.59134
1982	95.52336
1983	95.09102
1984	94.98543
1985	94.77774
1986	95.23696
1987	95.57854
1988	95.66064
1989	95.48593
1990	95.25484
1991	94.94761
1992	94.65399
1993	95.15939
1994	95.65114
1995	96.02632
1996	96.54852
1997	96.96351
1999	97.09463
2000	97.00001
2001	97.24078
2002	96.98865
2003	96.8464
2004	96.46033
2005	96.86078
2006	96.8636
2007	96.80331
2008	97.01005
2009	96.86722
2010	96.93236
2011	97.12963
2012	97.19151
2013	97.34874
2014	97.03694
2015	97.08145
2016	96.91094
2017	96.79802