Year	% of total primary
1970	10.3871603012085
1971	10.3163499832153
1972	10.0530996322632
1973	10.3675699234009
1974	10.3066501617432
1975	9.90684986114502
1976	10.1237001419067
1977	9.90423965454102
1978	9.92681980133057
1979	9.90732002258301
1980	9.95038986206055
1981	10.0991296768188
1982	10.0459499359131
1983	10.0213298797607
1984	9.99872970581055
1985	10.385009765625
1986	10.5041198730469
1987	10.62965965271
1988	10.7555599212646
1989	10.9429502487183
1990	11.0358896255493
1991	11.2039203643799
1992	11.5636396408081
1993	11.6750297546387
1994	11.883279800415
1995	11.8985996246338
1996	12.0196800231934
1997	12.4003601074219
1998	12.5509395599365
1999	12.5987997055054
2000	12.6715297698975
2001	12.7587795257568
2002	13.0386800765991
2003	13.2622098922729
2004	13.6457004547119
2005	14.0892601013184
2006	14.4021797180176
2007	14.7093200683594
2008	15.3020896911621
2009	15.4880304336548
2010	15.8538103103638
2011	16.2508296966553
2012	16.7739200592041
2013	17.0382404327393
2014	17.5034599304199
2015	17.7909908294678
2016	18.0717105865479
2017	18.2325401306152
2018	18.4024696350098
2019	18.6968803405762
2020	18.5527496337891
2021	17.45578956604
2022	17.8076190948486