Year	% net
1976	73.5037
1977	74.45136
1978	74.66047
1979	74.93188
1980	75.40982
1981	75.2583
1982	75.5513
1983	76.00301
1984	76.34863
1985	76.91678
1986	78.07873
1987	78.72408
1988	78.90815
1989	79.18489
1990	79.29505
1991	80.41374
1992	81.97614
1993	84.67176
1994	87.76758
1995	87.9679
1996	88.13118
1997	87.91018
1998	85.77184
1999	85.34951
2000	86.19667
2001	86.22596
2002	87.23515
2003	87.57485
2004	88.46528
2005	89.75332
2006	90.4529
2007	89.97486
2008	90.57837
2009	90.51895
2010	90.79728
2011	90.2992
2012	90.13646
2013	89.58374
2014	89.39284
2015	89.5662
2016	89.90253
2017	90.20529
2018	90.22215