Year	% net
1973	7.59073
1974	8.18867
1986	16.53225
1989	16.47078
1990	16.88337
1991	17.39823
1992	16.02055
1997	18.56885
1998	19.14915
1999	20.65364
2000	21.61453
2001	24.43304
2002	27.18772
2003	30.5263
2004	33.4259
2005	34.26441
2006	35.20626
2007	36.6388
2008	41.02578
2009	44.77694
2010	47.99076
2011	52.61018
2012	54.68609
2013	55.31584
2014	55.0955
2015	56.39829
2016	58.33642
2017	60.19768