Year	% net
1972	76.32854
1976	79.03076
1977	79.06834
1978	78.00978
1979	77.52895
1980	77.49769
1981	77.54903
1982	77.42984
1983	78.98378
1984	80.04986
1986	81.30017
1988	79.22874
1994	72.80447
1995	71.00091
1998	68.28556
1999	66.61659
2000	66.27138
2001	66.15033
2002	68.27762
2004	81.56315
2005	89.74576
2006	89.24665
2007	90.45893
2008	92.16696
2009	87.28261
2010	84.80889
2011	87.93907
2012	89.20566
2013	86.61205
2017	83.16745