Year	% net
1970	22.8055
1981	41.71262
1995	51.89509
1998	58.92529
1999	59.53589
2000	61.47621
2001	64.33569
2002	65.26672
2004	66.17207
2005	67.15178
2006	70.0323
2007	74.32157
2008	76.59316
2009	79.59229
2010	79.51214
2011	80.15817
2012	75.26713
2013	80.51175
2014	80.06639
2015	79.97777
2016	82.59675
2017	84.72109
2018	87.71031