Year	% net
1971	79.13283
1973	79.44559
1974	80.6499
1975	80.43633
1976	80.88395
1977	83.79094
1978	85.5475
1979	88.33894
1980	87.0204
1994	92.57643
1995	93.11275
1996	94.4018
1997	96.86744
1998	95.90437
1999	95.72803
2000	96.14464
2001	97.58054
2005	96.65463
2006	96.51678
2008	96.06828