Year	% net
1970	82.64755
1971	82.98282
1972	83.50226
1973	84.29716
1974	84.89521
1975	85.10188
1976	85.85403
1977	86.79493
1978	87.34987
1979	88.90941
1980	89.37124
1981	90.56664
1982	90.71428
1983	90.75877
1984	90.556
1985	91.00293
1986	90.72041
1987	90.83276
1988	90.52273
1989	89.76257
1990	90.3015
1991	90.64339
1992	91.27846
1993	91.56825
1994	91.04648
1995	90.91717
1996	91.31869
1997	90.48603
1999	93.29252
2000	93.92545
2002	93.8301
2003	92.98412
2004	93.48408
2005	94.45332
2006	94.27547
2007	94.02604
2008	94.9612
2009	94.99954
2010	95.00301
2011	94.77791
2012	94.99862
2013	93.77119
2014	93.6423
2015	93.59806
2016	93.90233
2017	93.87033
2018	93.8643