Year	% net
1975	50.76145
1976	53.31484
1977	56.05195
1981	60.67262
1983	58.6316
1984	57.04687
1985	57.97669
1986	54.72104
1999	80.6166
2000	74.9762
2001	74.17742
2002	74.24021
2003	73.76098
2004	78.58011
2005	77.72014
2011	73.96963
2013	69.21344
2014	69.10218
2015	68.27336
2016	69.11646
2017	70.21655
2018	71.72318