Year	% net
1972	32.02655
1973	35.09204
1974	35.65939
1975	37.6395
1976	38.92846
1977	41.37761
1978	42.68706
1979	45.10903
1980	47.41526
1981	49.8855
1982	50.62072
1983	51.09309
1984	51.26974
1985	50.58186
1986	49.51956
1987	48.98818
1988	50.2413
1989	50.03511
1990	49.79495
1991	51.06825
1992	51.6425
1993	52.21277
1994	52.85007
1995	53.23409
1996	52.54972
1997	54.50168
1998	55.24595
1999	55.86183
2000	58.02472
2001	59.43389
2002	61.52256
2003	63.98322
2004	66.40502
2005	68.34811
2006	69.77033