Year	% net
1975	96.26805
1976	93.67281
1977	94.38466
1979	98.10229
1980	98.46277
1981	97.67997
1983	98.99577
1984	97.77829
1985	96.86706
1986	97.00761
1987	97.49165
1988	95.03253
1989	98.8042
1990	97.65581
1991	96.04081
1993	91.73084
1999	90.21696
2000	91.46757
2001	91.50813
2002	91.44173
2003	90.29403
2004	91.99367
2015	88.5697
2016	84.4568
2017	82.74604
2018	81.26045