Year	% net
1970	28.25133
1981	47.299
1995	52.42518
1998	59.11605
1999	59.93842
2000	62.51048
2001	65.64313
2002	66.47532
2004	65.89962
2005	67.27638
2006	68.74822
2007	71.5351
2008	72.90413
2009	75.98753
2010	76.0262
2011	77.76211
2012	75.36994
2013	79.49385
2014	79.0072
2015	78.41994
2016	83.01147
2017	86.44261
2018	90.92061