Year	% net
1971	69.13764
1972	71.87652
1973	73.69326
1974	75.69932
1975	76.82385
1976	80.04422
1977	81.16168
1978	81.52763
1979	81.40867
1980	81.09597
1981	81.14488
1982	82.12824
1983	83.47393
1984	85.223
1985	85.32612
1986	88.60145
1987	88.32141
1988	86.30729
1989	84.6884
1990	83.74738
1991	83.69099
1992	84.40415
1993	85.83392
1995	90.92787
1996	90.87457
1997	89.45088
1999	90.99442
2002	89.33102
2003	88.12664
2004	88.73562
2005	86.907
2006	88.55384
2007	88.54171
2008	88.17683
2009	87.63294
2010	87.8786
2011	89.02126
2012	89.579
2015	92.54597
2016	93.17266
2017	93.16439