Year	% net
1970	21.11032
1971	21.22642
1972	21.37414
1973	22.68826
1974	23.16868
1975	24.45432
1976	25.92266
1977	27.79315
1978	29.60527
1979	31.04599
1980	32.17602
1981	32.65989
1982	34.1568
1983	35.3065
1984	36.57526
1985	37.99771
1986	39.77378
1987	40.88724
1988	41.37932
1989	42.05497
1990	44.54737
1991	44.71384
1992	43.76501
1993	44.38228
1994	46.19188
1995	46.28907
1996	46.40997
1997	47.67226
1998	49.06666
1999	50.59593
2000	51.92024
2001	53.24759
2002	54.05277
2003	55.7292
2004	57.48235
2005	57.5619
2006	57.46168
2007	57.23471
2008	58.28565
2009	60.34947
2010	60.67437
2011	62.26881
2012	62.45941
2013	61.08331
2014	61.53884
2015	62.06563
2016	62.55911
2017	63.06303
2018	63.51428