Year	% net
1971	6.86515
1972	7.65745
1973	8.48205
1974	9.10231
1975	10.14336
1976	11.10677
1977	12.03692
1978	13.14179
1979	13.7882
1980	14.2977
1981	15.14787
2012	39.66006
2013	41.01904
2014	43.96082
2015	45.01617
2016	45.99349