Year	% net
1997	80.58419
1998	80.94752
1999	83.02343
2000	84.71519
2001	87.21919
2002	89.00928
2003	90.64579
2004	90.40353
2005	90.16458
2006	90.18345
2007	89.98774
2008	89.90334
2009	89.32099
2010	89.13358
2011	88.55383
2012	89.06612
2013	89.72077
2014	89.69264
2015	88.9433
2016	89.13269
2017	89.05489