Year	% (cumulative)
1971	15.7837800979614
1981	31.3732395172119
1990	24.1687698364258
2000	40.8800010681152
2001	42.8499984741211
2002	43.1599998474121
2003	43.3899993896484
2004	43.5099983215332
2005	46.5900001525879
2006	47.689998626709
2007	48.5299987792969
2008	49.8699989318848
2009	50.8300018310547
2010	51.810001373291
2011	53.689998626709
2012	53.689998626709
2013	55.5900001525879
2014	56.9599990844727
2015	67.0573577880859
2016	72.2732315063477
2017	68.640998840332