Year	% net
1971	74.57173
1972	83.77437
1973	85.77034
1974	84.30361
1976	90.77534
1977	88.71769
1978	92.60219
1979	93.31216
1981	92.98722
1983	91.21989
1984	92.49984
1985	92.06867
1986	95.3049
1987	88.84785
1988	88.23307
1989	86.8906
1990	84.46598
1991	80.62631
1992	77.5297
1993	77.53987
1994	82.24454
2000	97.84263
2006	92.0173
2013	90.6385
2014	90.51796
2015	92.03463
2016	92.70992
2017	93.32709
2018	95.16615