Year	% net
1981	92.68579
1982	94.29359
1983	92.58319
1984	88.40193
1986	93.91955
1987	93.31287
1988	96.81855
1989	98.31281
1998	90.24974
1999	89.29798
2001	90.34012
2002	90.81896
2003	90.82528
2004	90.39647
2005	89.64806
2006	87.86851
2007	88.2367
2008	89.40371
2009	91.14398
2014	96.1798
2015	95.64566
2016	94.72036
2017	93.69001