Year	% of total primary
1970	29.0207500457764
1971	32.1016616821289
1972	25.3863105773926
1973	24.5660705566406
1974	23.9978809356689
1975	23.2160491943359
1976	22.4526195526123
1977	21.945629119873
1978	21.6881408691406
1979	21.2623596191406
1980	20.6674709320068
1981	20.0514793395996
1982	19.4683208465576
1983	18.7916393280029
1984	18.1521396636963
1985	17.4654502868652
1986	16.8186206817627
1987	16.2145195007324
1988	15.6433095932007
1989	14.7913303375244
1990	14.1561403274536
1991	13.3356704711914
1992	13.1704196929932
1993	12.622260093689
1994	12.1294097900391
1995	11.707070350647
1996	11.7667903900146
1997	11.6354198455811
1998	11.6219501495361
1999	11.3795900344849
2000	11.4202404022217
2001	11.6729097366333
2002	11.6176099777222
2003	11.2483396530151
2004	11.5574398040771
2005	11.8433904647827
2006	11.6944398880005
2007	12.3742799758911
2008	12.5548801422119
2009	13.4309902191162
2010	14.2700004577637
2011	17.5608196258545
2012	17.2341995239258
2013	17.4768199920654
2014	17.0631999969482
2015	17.502950668335
2016	17.6404991149902
2017	19.5401306152344
2018	21.34202003479
2019	21.3101005554199
2020	21.1995296478271
2021	22.0159702301025
2022	22.2605094909668