Year	% net
1970	25.56384
1981	44.54678
1995	52.1665
1996	53.24848
1997	53.44598
1998	59.02289
1999	59.7418
2000	62.00506
2001	65.00322
2002	65.88343
2004	66.03303
2005	67.21536
2006	69.37305
2007	72.88175
2008	74.67779
2009	77.71898
2010	77.70725
2011	78.92787
2012	75.31964
2013	79.99309
2014	79.52639
2015	79.18143
2016	82.80666
2017	85.58522
2018	89.30975