Year	% (cumulative)
1972	4.5
1981	10.52886
1993	20.74899
2004	12.51344
2005	16.06016
2006	16.94343
2007	18.21692
2008	18.20955
2009	18.75256
2010	20.87359
2011	21.24498
2012	22.15469
2013	21.33951
2014	21.11848
2015	20.87703
2018	21.90983