Year	% net
1971	56.27766
1972	56.39323
1973	54.80279
1974	53.93928
1975	59.73567
1976	61.46184
1977	60.59428
1978	61.76391
1979	62.99343
1980	63.3704
1988	68.92324
1990	68.15451
1991	66.47375
2011	82.91874
2016	90.25242
2017	88.71914