Year	% net
1976	96.79226
1979	96.17531
1981	93.15358
1982	93.16523
1983	91.57376
1984	90.89301
1985	94.43847
1986	93.83803
1987	94.10697
1988	96.14788
1989	97.64527
1992	95.62759
1993	94.67716
1994	93.04913
1996	95.75706
1998	91.8589
1999	88.98721
2001	89.53385
2002	89.63244
2003	89.90912
2004	89.35752
2005	88.55488
2006	86.79077
2007	87.09612
2008	88.12346
2009	89.88861
2014	95.36339
2015	95.0759
2016	94.36604
2017	93.7756