Year	% net
1986	85.9053
1987	90.06403
1988	91.24759
1989	92.68094
1990	91.72237
1991	92.57994
1992	92.6787
1993	92.0758
1994	91.20744
1995	90.05738
1996	89.49607
1997	89.03493
1998	91.37946
1999	93.81986
2000	93.94799
2001	94.09889
2002	94.14736
2003	93.99804
2004	94.19523
2005	93.97354
2006	93.56541
2007	94.82269
2008	94.86243
2009	95.18151
2010	95.50133
2011	95.92812
2012	95.49613
2013	95.44349
2014	95.46373
2015	95.51255