Year	% net
1985	93.12001
1986	94.49713
1987	96.17221
1988	97.09901
1989	97.93768
1990	98.87215
1991	98.8029
1992	97.88413
1993	96.76669
1994	96.47526
1995	97.04692
1996	96.23125
1997	96.08155
1998	95.89
1999	95.49974
2000	95.48713
2001	96.35083
2002	95.36432
2003	96.19089
2004	95.57977
2005	95.83351
2006	96.59466
2007	96.75123
2008	96.8388
2009	95.90614
2010	94.05366
2011	93.63206
2012	93.23706
2013	93.33195
2014	94.10513
2015	94.78767
2016	95.2928
2017	95.02639
2018	94.86607