Year	% net
1971	65.53423
1972	69.02473
1973	71.57332
1974	74.05477
1975	75.57064
1976	79.57087
1977	80.89294
1978	81.64654
1979	81.58852
1980	81.60496
1981	81.82735
1982	82.98648
1983	84.51994
1984	86.22055
1985	86.50565
1986	90.01309
1987	89.51587
1988	87.47191
1989	85.75114
1990	84.88268
1991	84.73341
1992	85.77496
1993	87.51836
1995	91.23474
1996	91.1966
1997	89.77776
1999	91.28279
2002	89.47284
2003	88.55526
2004	89.21885
2005	87.84559
2006	89.22556
2007	89.17282
2008	88.76454
2009	88.23375
2010	88.50049
2011	89.71146
2012	90.19554
2015	93.23838
2016	93.80068
2017	93.74044