Year	% net
1971	86.44477
1972	88.06389
1973	88.73368
1976	98.82915
1977	98.32617
1978	98.22735
1979	98.87614
1981	94.60567
1982	94.4972
1983	96.31603
1989	99.69313
1990	97.58751
1992	89.72294
1999	97.1169
2000	95.49268
2001	94.59061
2002	91.89692
2003	91.5808
2004	90.45634
2005	90.23547
2006	92.05669
2007	94.74497
2008	96.7412
2009	93.71878
2010	94.95407
2011	93.44599
2014	92.54496
2015	93.76577
2016	95.42938
2017	94.99257
2018	96.69287