Year	% (cumulative)
1971	4.39749002456665
1981	5.30117988586426
1991	7.57566976547241
2005	27.058780670166
2007	27.4019508361816
2008	28.1855697631836
2009	28.5659694671631
2010	28.7572498321533
2011	29.1374397277832
2012	29.8584995269775
2013	30.2990398406982
2014	30.083589553833
2015	31.251859664917
2016	31.8292999267578
2017	32.1651306152344
2018	33.064037322998
2019	33.4953918457031
2020	33.660343170166
2021	34.1247978210449