Year	% net
1998	57.10068
1999	57.47513
2000	58.5507
2001	59.18451
2002	59.76992
2003	60.73154
2004	61.7581
2005	62.74446
2006	63.44455
2007	64.90056
2008	65.94445
2009	66.50128
2010	68.27682
2011	69.97504
2012	70.32132
2013	71.99196
2014	73.04477
2015	73.0542
2016	72.90287
2017	73.48382
2018	73.57131