Year	% (cumulative)
1972	6.14489984512329
1981	12.8200302124023
1993	23.1561393737793
2004	13.2926502227783
2005	17.0253200531006
2006	17.9784698486328
2007	19.4716796875
2008	19.2809391021729
2009	19.7634391784668
2010	21.8527202606201
2011	21.5783500671387
2012	22.5916404724121
2013	22.1312103271484
2014	22.8073692321777
2015	20.9136505126953
2018	22.6931400299072