Year	% (cumulative)
1971	2.55789995193481
1981	3.24651002883911
1991	6.10451984405518
2005	23.8370304107666
2007	23.867000579834
2008	23.595760345459
2009	25.6225490570068
2010	26.1673908233643
2011	26.338830947876
2012	26.9906406402588
2013	27.8275604248047
2014	27.9757099151611
2015	29.1428203582764
2016	29.9815807342529
2017	30.6283702850342
2018	31.2313499450684
2019	32.1179618835449
2020	32.3859786987305
2021	33.1902503967285