Year	% of total primary
1971	51.6663093566895
1972	51.3528709411621
1973	53.9839096069336
1974	52.1952896118164
1975	52.1607284545898
1976	51.5710601806641
1981	53.0020217895508
1982	52.9887619018555
1983	52.9912605285645
1984	53.4123802185059
1985	50.6894989013672
1986	54.6029815673828
1987	55.1553192138672
1988	55.6312599182129
1989	55.7695388793945
1990	56.0449409484863
1991	55.9834098815918
1992	55.9401588439941
1993	55.8393898010254
1994	55.6343688964844
1995	55.3353691101074
1996	55.1851387023926
1999	55.0530090332031
2000	54.4482498168945
2001	54.4066581726074
2002	54.3068618774414
2003	54.1783790588379
2004	54.6596183776855
2005	54.5525207519531
2006	54.4255790710449
2007	54.2639312744141
2008	54.0821113586426
2009	54.0604705810547
2010	53.829460144043
2011	53.7555313110352
2012	53.593090057373
2013	54.2579383850098
2014	54.3250198364258
2015	53.9916610717773
2016	53.9715805053711
2017	54.4343681335449
2018	54.2202186584473
2019	54.1783714294434
2020	54.2216186523438
2021	54.1244010925293