Year	% net
1986	89.53864
1987	91.34614
1988	92.28616
1989	93.43545
1990	94.25785
1991	94.63891
1992	94.30534
1993	93.72314
1994	92.63922
1995	91.4812
1996	90.77978
1997	90.3573
1998	92.06558
1999	94.07662
2000	94.36661
2001	94.87836
2002	95.31752
2003	95.63262
2004	95.85251
2005	95.73099
2006	95.00191
2007	95.55326
2008	95.91793
2009	95.81115
2010	95.66169
2011	95.55025
2012	95.53442
2013	95.28401
2014	95.3644
2015	95.40497
2016	95.49673
2017	95.31941
2018	95.47259