Year	% net
1977	44.36807
1978	48.39695
1979	52.35795
1982	61.44696
1983	73.18704
1984	67.50669
1985	73.33706
1986	77.61625
1987	74.01282
1989	75.30837
1994	87.66736
1995	89.73895
1997	81.57764
1998	82.72236
1999	81.91997
2000	85.80863
2001	85.80281
2002	81.2614
2003	80.75826
2004	82.12857
2005	83.1024
2006	83.7383
2008	81.22738
2009	82.70062
2010	85.15745
2011	87.97455
2012	82.73486
2013	83.90717
2014	87.55684
2015	90.90495
2016	92.29972
2017	90.44694
2018	86.97008