Year	% net
1998	58.04937
1999	59.42648
2000	60.51936
2001	61.54908
2002	62.01699
2003	63.87146
2004	65.92082
2005	67.32756
2006	68.70031
2007	70.97545
2008	71.05281
2009	73.0879
2010	75.24783
2011	76.98839
2012	76.80508
2013	77.69285
2014	80.50371
2015	80.36012
2016	80.50683
2017	80.24399
2018	80.78035