Year	% of total primary
1970	8.38082027435303
1971	11.968090057373
1972	12.5999298095703
1973	12.3198299407959
1974	9.67621994018555
1975	7.23584985733032
1976	8.05366039276123
1977	7.95806980133057
1978	8.21566009521484
1979	7.80979013442993
1980	7.4253101348877
1981	6.71368980407715
1982	6.7146201133728
1983	6.6472601890564
1984	6.62112998962402
1985	6.57679986953735
1986	6.61183977127075
1987	6.52905988693237
1988	7.07837009429932
1989	7.21401977539062
1990	7.73301982879639
1991	8.0554895401001
1992	8.69499969482422
1993	9.0221700668335
1994	9.38329029083252
1995	10.3496503829956
1996	10.8028802871704
1997	11.1614103317261
1998	11.6358699798584
1999	11.9950304031372
2000	12.4009304046631
2001	12.5865802764893
2002	12.6903896331787
2003	12.7863702774048
2004	13.0108003616333
2005	13.3336296081543
2006	13.2753801345825
2007	13.1082401275635
2008	12.6889400482178
2009	13.1535701751709
2010	13.1061000823975
2011	12.7127599716187
2012	12.5868797302246
2013	12.6219902038574
2014	12.3790702819824
2015	12.5413904190063
2016	12.6127796173096
2017	12.7428703308105
2018	13.1493797302246
2019	13.1318101882935
2020	13.1881504058838
2021	13.3763303756714
2022	13.421669960022