Year	% net
1977	49.52034
1978	49.22443
1979	50.24547
1980	51.61776
1981	50.98676
1982	52.35966
1983	54.21818
1984	51.35726
1991	67.8667
1992	64.05243
1993	65.11097
1994	66.4349
2005	88.24888
2006	89.34426
2007	87.6805
2008	87.52486
2009	89.11406
2010	90.15449
2011	91.16476
2012	93.3478
2013	91.37788
2014	87.44971
2015	85.06305
2016	83.7965
2017	84.04573
2018	82.64549