Year	% net
1971	95.91674
1972	97.544
1973	96.80779
1974	96.44532
1975	96.7839
1976	97.68954
1977	96.78439
1978	97.12083
1979	98.75101
1980	99.96693
1981	99.94785
1982	99.81309
1983	99.7587
1984	99.13846
1985	98.57461
1986	98.27344
1987	99.4696
1988	99.88403
1989	99.88231
1990	99.77703
1991	99.73981
1992	99.57954
1993	99.35196
1994	99.00819
1995	98.51563
1996	98.24344
1997	98.30431
1998	97.72215
1999	98.50236
2000	99.06072
2001	98.11869
2002	97.73171
2003	98.5255
2004	98.19463
2005	99.38856
2006	99.40966
2007	99.47129
2008	99.50574
2009	99.49475
2010	98.38177
2011	98.88635
2012	97.84902
2013	95.3693
2014	95.818
2015	97.98472
2016	96.86178
2017	97.25516