Year	% net
1986	90.45974
1987	93.14667
1988	94.39944
1989	95.46081
1990	94.3869
1991	95.00256
1992	94.90064
1993	94.1595
1994	93.19972
1995	91.85664
1996	90.98903
1997	90.29686
1998	92.22702
1999	94.25017
2000	94.34921
2001	94.45753
2002	94.40174
2003	94.35906
2004	94.49193
2005	94.3309
2006	93.88781
2007	95.01604
2008	95.07917
2009	95.38067
2010	95.49505
2011	95.68272
2012	95.68114
2013	95.46491
2014	95.6547
2015	95.86588