Year	% net
1986	89.80484
1987	90.00545
1988	88.5379
1989	87.07852
1990	85.62007
1991	85.38716
1992	87.15996
1993	88.97001
1994	90.01767
1995	90.67475
1996	89.39361
1997	89.6473
1998	89.89935
1999	88.17004
2000	88.02895
2001	89.09696
2002	86.78393
2003	89.63641
2004	90.64461
2005	90.19156
2006	89.581
2007	89.54514
2008	89.54421
2009	89.94213
2010	88.85594
2011	90.11209
2012	90.46793
2013	90.2044
2014	91.04777
2015	92.64743
2016	92.81398
2017	93.62134
2018	93.61716