Year	% (cumulative)
1970	14.6000003814697
1975	19.7000007629395
1980	30.8351993560791
1985	43.2129898071289
2005	46.413158416748
2006	48.9308815002441
2007	49.495288848877
2008	53.7111206054688
2012	55.6178092956543
2013	55.763729095459
2015	58.4748001098633
2017	59.5261116027832
2018	60.0143013000488