Year	% net
1998	62.02646
1999	62.45265
2000	63.32155
2001	64.1516
2002	65.11596
2003	63.70023
2004	64.80967
2005	65.50703
2006	65.71195
2007	65.81279
2008	68.04854
2009	69.24065
2010	69.8319
2011	70.33453
2012	70.39677
2013	74.03392
2014	74.19345
2015	74.98294
2016	75.78448
2017	75.78274
2018	75.93138