Year	% net
1986	89.75621
1987	92.04399
1988	93.17423
1989	93.95534
1990	94.31974
1991	94.35787
1992	94.04846
1993	93.57585
1994	92.64975
1995	91.51811
1996	90.83551
1997	90.16442
1998	92.29508
1999	94.60236
2000	94.89718
2001	94.99997
2002	95.10867
2003	95.31197
2004	95.63184
2005	95.59285
2006	94.74437
2007	95.45125
2008	96.1566
2009	96.09048
2010	96.06111
2011	96.1477
2012	96.32961
2013	95.9794
2014	96.23772
2015	96.28923
2016	96.52503
2017	96.50654