Year	% (cumulative)
1975	13.8000001907349
1980	22.1471004486084
1985	32.4959411621094
1988	29.9586505889893
2005	30.0950202941895
2006	31.3317909240723
2007	30.7113304138184
2008	32.1678810119629
2012	34.2641792297363
2013	34.0998382568359
2015	36.3197784423828
2017	38.1961212158203
2018	39.2844505310059