Year	% of total primary
1972	4.41695022583008
1973	4.18803977966309
1974	4.01152992248535
1975	3.6898500919342
1976	3.44175004959106
1977	3.29303002357483
1978	3.2948100566864
1979	3.27653002738953
1980	3.23644995689392
1981	3.19957995414734
1982	3.20939993858337
1983	3.26602005958557
1984	3.28919005393982
1985	3.27292990684509
1986	3.28257989883423
1987	3.35050010681152
1988	3.42195010185242
1989	3.50091004371643
1990	3.54561996459961
1991	3.56942009925842
1992	3.49168992042542
1993	3.51692008972168
1994	3.62730002403259
1995	3.73957991600037
1996	3.87191009521484
1997	3.95472002029419
1998	4.22018003463745
1999	4.43157005310059
2000	4.32156991958618
2001	4.6094799041748
2002	4.96947002410889
2003	5.38472986221313
2004	5.47037982940674
2005	5.84535980224609
2006	6.07989978790283
2007	6.75436019897461
2008	6.72190999984741
2009	7.09085988998413
2010	7.43321990966797
2011	7.79804992675781
2012	8.08372974395752
2013	8.42053985595703
2014	8.81398010253906
2015	9.37226009368896
2016	9.71051979064941
2017	9.97521018981934
2018	10.4594497680664
2019	10.7333602905273
2020	10.9757299423218
2021	10.9745597839355
2022	10.8697595596313