Year	% net
1971	13.22033
1972	15.95872
1973	20.68498
1974	28.01731
1975	33.17223
1976	41.50767
1977	45.90826
1978	52.13122
1979	55.45254
1980	57.72015
1981	55.33849
1983	58.4499