Year	% net
1977	22.13215
1981	25.35542
1998	43.26009
1999	45.34096
2000	45.82902
2001	45.93751
2002	46.63762
2003	46.30024
2004	44.634
2005	42.53033
2006	43.35556
2007	44.22933
2009	44.50241
2010	44.99704
2011	43.88896
2012	46.34225
2013	52.1058
2015	55.32819
2016	61.67048
2017	58.82658
2018	61.06971