Year	% (cumulative)
1975	18.7307891845703
1980	26.4976406097412
1985	31.3604793548584
1988	32.4937896728516
2005	23.1198902130127
2006	22.9332809448242
2007	23.2185802459717
2008	23.8512592315674
2012	31.8321800231934
2013	25.1391792297363
2015	26.3828201293945
2017	26.6608295440674
2018	27.1404495239258