Year	% net
1970	50.13616
1971	49.60795
1972	51.22741
1973	53.79911
1974	53.37144
1975	55.20036
1976	55.82257
1977	58.23049
1978	57.44339
1979	58.358
1980	60.15884
1981	62.11025
1982	63.88353
1983	65.25473
1984	66.21501
1985	66.11699
1986	66.62846
1987	65.90043
1988	67.28677
1989	68.89502
1990	67.79542
1991	68.42889
1992	68.92171
1993	70.31151
1994	71.54919
1995	71.06154
1996	71.28039
1997	71.4842
1998	71.32036
1999	72.16595
2000	73.67382
2001	74.19937
2002	74.48508
2003	78.80187
2004	80.18948
2005	81.30851
2006	82.30095
2007	84.06766
2008	84.17619
2009	84.71574
2010	85.1884
2011	85.34961
2012	85.4769
2013	85.45898
2014	85.54304
2015	85.29273
2016	85.53292
2017	85.46826
2018	85.53799