Year	% net
1970	75.33835
1973	79.31982
1980	83.43804
1981	88.26209
1982	89.06594
1985	94.67306
1988	90.5601
1993	90.02087
1995	84.90604
1996	84.5073
1997	84.03117
1998	94.87532
1999	96.09633
2000	96.78535
2001	97.54243
2002	97.50977
2003	98.03598
2004	96.721
2005	96.58075
2006	96.4861
2007	96.36325
2008	96.38973
2009	95.95255
2010	96.60304
2011	96.50894
2012	91.85927
2013	93.73238
2014	92.54948
2015	92.73258
2016	95.29
2017	94.91894
2018	95.65167