Year	% net
1975	55.32495
1976	57.82786
1977	59.18727
1981	64.41112
1983	61.58163
1984	59.63479
1985	60.48277
1986	58.11748
1999	81.20214
2000	76.31857
2001	75.43941
2002	75.81995
2003	75.90072
2004	80.86763
2005	80.61632
2011	76.80378
2013	72.92916
2014	72.78254
2015	71.87973
2016	72.66633
2017	73.20201
2018	73.96802