Year	% net
1970	51.62585
1973	72.03309
1976	76.7823
1977	73.18313
1978	72.14783
1981	68.55957
1983	65.58304
1984	64.46519
1985	62.89953
1986	62.08812
1987	61.20893
1988	71.93169
1989	71.90344
1990	74.92288
2005	93.68999
2006	93.43051
2008	92.56719
2009	92.54123
2010	90.53203