Year	% net
1986	88.10165
1987	88.29886
1988	87.0869
1989	85.87593
1990	84.65892
1991	84.64996
1992	86.62749
1993	88.65336
1994	89.8368
1995	89.97495
1996	89.32095
1997	89.30873
1998	89.29432
1999	87.31304
2000	86.91654
2001	87.99579
2002	86.61102
2003	88.93807
2004	89.40924
2005	89.02733
2006	88.70541
2007	88.66419
2008	88.86847
2009	88.9192
2010	88.16823
2011	89.47648
2012	89.55233
2013	89.64119
2014	89.96159
2015	91.36782
2016	92.79179
2017	93.07327
2018	93.06775