Year	% (cumulative)
1975	16.7999992370605
1980	24.9235305786133
1985	31.719970703125
1988	31.5011596679688
2005	25.3631706237793
2006	25.561710357666
2007	25.6212406158447
2008	26.533519744873
2012	32.6966209411621
2013	28.3367500305176
2015	29.9012699127197
2017	30.6030693054199
2018	31.1964302062988