Year	% net
1972	43.85323
1973	46.34372
1974	47.03468
1975	48.61597
1976	49.83838
1977	51.35124
1978	52.55325
1979	54.50947
1980	56.04746
1981	57.66945
1982	58.32479
1983	58.87126
1984	58.51148
1985	57.83258
1986	56.78872
1987	56.3317
1988	57.15039
1989	56.75093
1990	56.36239
1991	57.29385
1992	57.53379
1993	57.88371
1994	58.35726
1995	58.77708
1996	58.17758
1997	59.90446
1998	60.39429
1999	60.64672
2000	62.69524
2001	63.98298
2002	65.83691
2003	67.95849
2004	70.10669
2005	71.86135
2006	72.8481