Year	% net
1972	77.95204
1973	78.48824
1974	79.07802
1975	80.05568
1976	80.1124
1977	83.59573
1978	81.3039
1979	78.6053
1980	79.26057
1981	82.57425
1982	88.51138
1983	91.63173
1984	94.81689
1985	99.90822
1986	98.41281
1987	99.64917
1988	99.45495
1989	99.32785
1990	97.1773
1991	92.62251
1993	92.76294
1994	93.73893
1995	94.68318
1996	96.98175
1997	97.90364
1998	95.79899
1999	92.75756
2000	93.22731
2001	92.75219
2002	94.33415
2003	93.72392
2004	94.39046
2005	96.02008
2006	96.03757
2007	96.515
2008	96.67636
2009	96.5883
2010	96.50869
2011	96.47593
2012	93.66061
2013	96.03009
2014	96.16563
2015	96.13651
2016	94.94084
2017	95.80694
2018	94.80512