Year	% (cumulative)
1981	33.849910736084
1991	45.7153091430664
2001	37.3602104187012
2006	45.9588394165039
2011	52.5431709289551
2012	50.9888381958008
2014	50.9253196716309
2015	48.717041015625
2016	50.7586708068848
2017	52.0609741210938
2018	53.3200416564941
2019	53.040210723877
2020	54.1097602844238