Year	% net
1970	48.97655
1971	45.47383
1972	46.83257
1973	49.92005
1974	54.27965
1975	61.02754
1976	65.59571
1977	69.79238
1978	70.47779
1979	71.93308
1980	76.10508
1981	80.6789
1983	85.62017
1984	86.37615
1985	88.6703
1986	89.85557
1987	90.76857
1988	91.24606
1989	91.89309
1990	91.56383
1991	93.73882
1992	93.09434
1993	92.69135
1994	92.66993
1995	83.12641
1996	83.61821
1998	84.55472
1999	85.06617
2000	85.93266
2001	87.25764
2002	87.32834
2003	87.47464
2004	88.40905
2005	87.65819
2006	88.6352
2007	87.27144
2008	85.99029
2009	85.5554
2012	87.75564
2013	88.02718
2014	87.65678