Year	% net
1974	82.51544
1975	82.42661
1976	83.29676
1977	83.69408
1978	84.25203
1979	84.04818
1980	91.13936
1981	91.07724
1982	93.32113
1983	92.27789
1984	91.45693
1985	91.91825
1986	93.54713
1987	95.29744
1988	96.38485
1989	97.48675
1990	98.55734
1991	98.80354
1992	97.90266
1993	96.87282
1994	96.25124
1995	97.01874
1996	96.08971
1997	95.95445
1998	95.80555
1999	95.47928
2000	95.44662
2001	95.64605
2002	94.73523
2003	95.53448
2004	94.84227
2005	94.96574
2006	95.65253
2007	96.20578
2008	96.26419
2009	95.04202
2010	93.79489
2011	92.90273
2012	93.33829
2013	93.35277
2014	93.73903
2015	94.37224
2016	95.48883
2017	95.08227
2018	95.17325