Year	% net
1971	24.23028
1972	25.2965
1973	26.88708
1974	28.38147
1976	37.63203
1977	37.69994
1978	44.28792
1979	49.35026
1980	54.24183
1981	57.25422
1983	63.41126
1984	63.66883
1985	66.6772
1986	69.4572
1987	61.92063
1988	63.24087
1990	66.2955
1991	67.93879
1992	67.7974
1993	73.98589
1994	76.09208
1998	76.89985
1999	74.43684
2002	76.91573
2004	91.83049
2005	90.04446
2006	84.17814
2010	93.8946