Year	% net
1971	79.53869
1973	80.0407
1974	80.97535
1975	80.34071
1976	80.7904
1977	83.90445
1978	85.77794
1979	88.93417
1980	87.55129
1994	91.98211
1995	92.52188
1996	93.75276
1997	96.26485
1998	95.2353
1999	94.95655
2000	95.58856
2001	96.80904
2002	97.41598
2003	97.01792
2005	95.95781
2006	95.93721
2007	96.72017
2008	94.52771
2009	92.34961
2010	92.62287
2011	91.98807
2012	91.67788
2013	91.50564
2014	91.35484
2015	91.6503
2016	91.66046
2017	91.64154
2018	90.94167