Year	% net
1985	71.66962
1986	72.41499
1987	72.85643
1988	72.47353
1989	72.12857
1990	72.04203
1991	72.89781
1992	74.00836
1993	76.20674
1994	78.03891
1995	78.76675
1996	79.22977
1997	79.38765
1998	79.3241
1999	79.21714
2000	80.08977
2001	81.52645
2002	81.92525
2003	83.3132
2004	84.18275
2005	84.98548
2006	85.20968
2007	85.24645
2008	85.44197
2009	85.20094
2010	85.57344
2011	86.02198
2012	85.84729
2013	87.04059
2014	87.72014
2015	88.46915
2016	89.00189
2017	89.3494
2018	89.36801