Year	% net
1974	84.99388
1985	91.98281
1986	92.91951
1987	92.59654
1988	94.28279
1989	94.27289
1990	96.02125
1991	95.3153
1992	95.50193
1993	93.07021
1994	92.24939
1995	91.64519
1997	92.04438
1999	94.97874
2000	95.8553
2001	96.39444
2002	96.71826
2003	97.15144
2004	97.47864
2005	97.79379
2006	98.05813
2007	98.52059
2008	97.74906
2009	95.35128
2010	96.08606
2011	95.21277
2012	92.722
2013	93.15272
2014	94.56716
2015	94.63188
2016	94.05097
2017	87.90006