Year	% net
1977	51.37552
1978	51.04478
1979	52.21725
1980	54.10249
1981	53.96242
1982	54.90979
1983	57.03768
1984	54.28311
1991	71.65753
1992	68.13667
1993	67.53283
1994	69.57298
2005	87.98015
2006	89.83722
2007	88.49667
2008	88.24747
2009	89.74596
2010	90.67793
2011	91.41084
2012	94.23704
2013	93.16588
2014	88.81411
2015	86.98323
2016	85.52219
2017	85.63814
2018	84.048