Year	% (cumulative)
1970	2.5
1980	5.8
1991	11.76038
2003	15.30109
2006	18.18313
2008	18.98166
2009	19.97506
2010	20.30522
2011	20.40739
2012	21.47392
2013	21.3466
2014	21.48547
2015	21.13941
2016	21.44456