Year	% of relevant age group
1972	20.8928508758545
1973	30.7271003723145
1974	32.5650482177734
1975	35.0492401123047
1976	36.4191284179688
1977	38.7176895141602
1978	39.7495918273926
1979	40.1315383911133
1980	41.2982711791992
1983	45.316219329834
1985	49.5321884155273
1986	50.4533386230469
1987	48.0794296264648
1988	46.920238494873
1989	46.5654907226562
1991	47.4697914123535
1992	48.6890296936035
1993	49.4839096069336
1996	51.2680206298828
1997	54.2934989929199
1999	54.1548690795898
2000	58.0520286560059
2001	60.7313003540039
2002	64.139892578125
2003	66.1213073730469
2004	70.2697982788086
2005	73.2031936645508
2006	75.08154296875
2007	79.5153427124023
2008	83.3151092529297
2009	83.2838973999023
2010	81.9811325073242
2011	81.7425003051758
2012	83.0614395141602
2013	84.1249465942383
2014	81.1091003417969
2015	80.4309387207031
2016	78.9536437988281
2017	76.9513320922852