Year	% net
1979	75.34568
1980	75.71297
1982	85.63146
1983	87.75465
1984	89.0043
1986	89.97715
1991	86.79371
1993	88.09414
2000	86.34144
2003	86.52539
2004	86.02025
2005	83.78781
2006	87.67662
2007	82.27979
2008	85.8893
2009	85.05423
2010	85.78627
2011	86.65916
2012	83.6711
2013	80.13631
2014	79.52522
2015	78.78149
2016	80.43124
2017	80.92844