Year	% net
1973	55.79117
1974	59.16065
1975	61.62457
1976	63.83371
1977	66.02593
1978	67.71829
1979	68.4216
1980	69.7613
1981	70.31687
1982	70.30168
1983	70.15331
1984	71.42914
1985	72.31578
1986	74.06331
1987	75.81019
1988	77.25058
1989	78.69119
1990	79.52591
1991	81.62065
1992	83.17855
1993	83.2644
1994	83.79624
1995	84.39233
1996	84.43281
1997	84.29735
1999	86.58871
2000	87.66998
2001	89.61183
2002	90.75677
2003	91.10768
2004	91.64398
2005	91.86275
2006	91.96863
2007	94.30325
2008	95.52681