Year	% (cumulative)
1972	4.5
1981	10.5288600921631
1993	20.7489891052246
2004	12.5134401321411
2005	16.0601596832275
2006	16.9434299468994
2007	18.2169208526611
2008	18.2095508575439
2009	18.7525596618652
2010	20.8735904693604
2011	21.2449798583984
2012	22.1546897888184
2013	21.3395099639893
2014	21.8895797729492
2015	20.8770294189453
2018	21.9098300933838