Year	% net
1971	3.57855
1972	3.61288
1973	4.00769
1974	3.95896
1991	5.54052
2008	27.69524
2009	28.78149
2010	30.67392
2011	31.98852
2013	33.11983
2014	35.01947
2015	31.36945
2016	32.53744
2017	29.34611
2018	29.92706