Year	% net
1972	26.00015
1973	27.54518
1974	28.92891
1975	31.27078
1976	33.64236
1977	35.7477
1978	37.42727
1979	38.64081
1980	40.70191
1981	42.01376
1982	41.00272
1983	41.84864
1984	41.68505
1985	41.25202
1986	41.48309
1987	40.72161
1988	41.20792
1989	40.94381
1990	40.1761
1991	41.80602
1992	41.33829
1993	41.27359
1994	42.52779
1995	44.54874
1996	44.52156
1997	47.49886
1998	47.98481
1999	48.32057
2000	50.66129
2001	53.01202
2002	57.2739
2009	74.90432
2015	78.10684
2016	78.33798