Year	% net
1970	53.12263
1971	49.56221
1972	51.34131
1973	54.88695
1974	59.53586
1975	67.11246
1976	71.9274
1977	76.23953
1978	76.78652
1979	78.23757
1980	82.65349
1981	87.01356
1983	91.66206
1984	92.07417
1985	93.95577
1986	93.86721
1987	94.3179
1988	94.75767
1989	94.91828
1990	94.99855
1991	97.27605
1992	96.22717
1993	95.38295
1994	95.18357
1995	85.28204
1996	85.60003
1998	86.27581
1999	86.88879
2000	87.82856
2001	89.09618
2002	88.91289
2003	89.12015
2004	88.43064
2005	89.11949
2006	89.63873
2007	88.32062
2008	87.16181
2009	86.38464
2012	88.64898
2013	88.75808
2014	88.10205