Year	% net
1971	97.79763
1972	97.81244
1977	94.51584
1979	99.11278
1980	99.65606
1982	97.76446
1983	95.84342
1985	95.09114
1986	97.59173
1992	99.21433
1993	97.82435
1994	97.7116
1995	98.85628
1997	99.98995
1999	96.02289
2000	95.72177
2001	95.66658
2002	95.61968
2003	95.39752
2004	95.47089
2008	98.31908
2009	97.97137
2010	97.51143
2011	98.74835
2012	98.83046
2013	98.74117
2014	97.90548
2015	98.6654
2016	99.11794