Year	% (cumulative)
1970	4
1980	6.1
1991	12.00991
2003	13.68345
2006	16.20843
2008	17.24615
2009	17.82052
2010	18.24677
2011	18.40534
2012	18.80334
2013	19.04036
2014	18.78469
2015	18.57615
2016	19.42225