Year	% net
1974	38.48482
1975	39.85312
1998	72.26102
1999	74.09156
2000	76.6439
2001	77.00817
2002	76.86968
2003	76.25386
2004	75.70999
2005	74.68905
2006	74.10481
2007	73.64578
2008	74.25696
2009	76.37201
2010	78.50932
2011	79.71058
2012	82.54345
2013	84.18274
2014	85.02421
2015	86.0714
2016	87.66393
2017	88.61459