Year	% net
1972	93.53554
1973	94.4193
1974	95.09471
1980	96.36885
1981	94.41839
1982	93.28839
1983	93.08228
1984	92.1089
1985	90.05032
1986	90.29418
1987	91.73722
1988	91.36786
1989	91.67703
1990	91.89559
1991	91.71904
1992	94.2409
1993	95.03094
1994	97.24664
1995	97.14267
1996	98.55066
1997	98.23953
1998	96.41434
1999	97.23299
2000	97.27999
2003	97.01449
2004	97.00437
2005	96.48194
2006	96.1051
2007	95.99335
2008	95.88886
2009	97.51779
2010	98.20597
2011	98.28971
2012	97.7171
2013	97.62517
2014	95.08158
2015	93.86373
2016	94.35613
2017	95.40883
2018	97.5384