Year	% net
1974	40.49867
1975	41.97323
1998	74.40915
1999	76.26566
2000	78.48781
2001	78.94955
2002	78.81052
2003	78.51365
2004	78.53653
2005	77.93493
2006	77.80917
2007	77.68491
2008	78.65304
2009	80.56529
2010	82.09918
2011	83.52317
2012	85.89363
2013	87.09754
2014	87.6325
2015	88.44048
2016	89.88468
2017	90.79605