Year	% net
1970	78.64393
1972	70.46281
1975	78.20262
1976	79.11909
1977	80.16302
1978	81.88567
1979	83.19155
1980	85.32919
1981	87.31095
1983	87.53933
1984	87.24532
1985	87.2404
1986	86.14522
1987	86.99188
1988	88.54602
1989	90.62521
1990	92.16674
1991	94.21239
1992	85.96722
1993	95.2745
1994	91.38842
1996	94.52527
1999	96.04743
2000	97.41576
2001	97.10807
2002	95.06094
2003	94.2893
2004	93.82272
2005	94.54344
2006	92.83664
2007	90.97908
2008	89.30019
2009	88.30433
2010	87.98466
2011	87.82389
2012	87.26503