Year	% net
1973	23.92941
1979	34.82921
1981	33.67767
1982	33.60308
1983	44.84728
1985	48.04056
1986	47.21884
1987	43.84901
1989	40.05235
1991	38.90162
1992	37.32364
1993	35.89831
1994	36.62206
1995	38.63597
1998	43.11135
1999	46.9813
2000	50.97578
2001	55.67854
2002	52.89554
2004	66.02418
2005	71.27924
2006	75.39822
2007	80.40001
2008	83.94941
2009	85.455
2010	86.69391
2011	84.73091
2012	85.02275
2013	86.15052
2014	87.33514
2015	88.76509
2016	88.72956
2017	88.22894
2018	92.4766