Year	% of total primary
1970	8.12549018859863
1971	8.0401496887207
1972	7.79921007156372
1973	7.50619983673096
1974	7.15720987319946
1975	6.66876983642578
1976	6.38477993011475
1977	5.81260013580322
1978	5.30182981491089
1979	4.68910980224609
1980	4.45829010009766
1981	4.14439010620117
1982	4.01149988174438
1983	3.79589009284973
1984	4.15940999984741
1985	3.78139996528625
1986	3.46507000923157
1987	3.4307599067688
1988	3.23348999023438
1989	3.24349999427795
1990	3.30719995498657
1991	3.1828498840332
1992	3.30795001983643
1993	3.44937992095947
1994	3.73166990280151
1995	3.70862007141113
1996	4.18020009994507
1997	4.29732990264893
1998	4.3915901184082
1999	4.55593013763428
2000	4.77691984176636
2001	5.06445980072021
2002	5.16404008865356
2003	5.25546979904175
2004	5.24776983261108
2005	5.48390007019043
2006	5.85121011734009
2007	6.15946006774902
2008	6.44324016571045
2009	6.72390985488892
2010	6.92069005966187
2011	7.1594500541687
2012	7.33407020568848
2013	7.44084978103638
2014	7.69995021820068
2015	8.38879013061523
2016	8.49691963195801
2017	8.87430953979492
2018	9.15717029571533
2019	9.4484395980835
2020	9.72089958190918
2021	9.26749038696289
2022	9.35509967803955