Year	% net
1976	76.25555
1977	77.03062
1979	76.79625
1980	76.98573
1981	77.14668
1982	77.4243
1983	78.38809
1985	80.90127
1986	81.31056
1987	81.5499
1988	81.63866
1989	82.00271
1990	82.68329
1992	88.46125
1993	89.6024
1994	95.50216
1995	96.21678
1996	95.53034
1997	94.93124
1999	90.10899
2000	89.91505
2001	89.6317
2002	89.28409
2003	89.03434
2004	88.89251
2005	92.63271
2006	92.66312
2007	92.60787
2008	92.59771
2009	92.6832
2010	92.55883
2011	92.86607
2012	93.22666
2013	93.39347
2014	92.95679
2015	93.58103
2016	93.95576
2017	94.66595