Year	% net
1983	75.13417
1984	75.89377
1985	76.07023
1986	76.83735
1987	77.27301
1988	76.92701
1989	76.76111
1990	76.64903
1991	77.6908
1992	78.90368
1993	81.25825
1994	83.2342
1995	83.74972
1996	84.14516
1997	84.23718
1998	83.77723
1999	83.46767
2000	83.89104
2001	84.70912
2002	84.9358
2003	86.18926
2004	86.83769
2005	87.43483
2006	87.37573
2007	87.21115
2008	87.53733
2009	87.8061
2010	87.93087
2011	88.15138
2012	88.29552
2013	88.67842
2014	89.1936
2015	89.87371
2016	90.53649
2017	90.745
2018	90.81931