Year	% net
1971	49.26928
1972	52.15357
1973	57.03425
1974	60.27251
1975	57.23604
1976	62.0989
1977	62.72218
1978	61.56679
1979	62.09664
1980	62.85698
1981	62.89118
1982	62.10306
1983	62.76542
1994	90.5196
1995	90.55158
1996	90.86582
1997	90.45496
1999	89.56057
2000	89.4389
2001	89.373
2002	93.13152
2003	94.34654
2004	94.56854
2005	95.28755
2006	95.12994
2007	96.30041
2008	96.70051
2009	96.45937
2010	89.65071
2011	90.62311
2012	92.9666
2013	93.98998
2014	95.50686
2015	95.10285
2016	94.13876
2017	95.3969