Year	% (cumulative)
1971	25.7472496032715
1981	38.127269744873
1991	39.2678985595703
2005	66.9239883422852
2007	64.9115371704102
2008	62.9571800231934
2009	68.0644226074219
2010	69.2499084472656
2011	69.0692901611328
2012	69.8329696655273
2013	70.5287933349609
2014	71.6085205078125
2015	72.4668502807617
2016	73.1191329956055
2017	73.7654037475586
2018	74.2007522583008
2019	75.3927764892578
2020	75.7792282104492
2021	76.5259399414062