Year	% of total primary
1970	17.2260398864746
1971	17.2061195373535
1972	16.2717990875244
1973	15.3913698196411
1974	16.0752601623535
1975	16.7446002960205
1976	17.4498805999756
1977	16.6064205169678
1978	15.7615203857422
1979	14.9014301300049
1980	14.1398696899414
1981	13.2606601715088
1982	12.346079826355
1983	11.4740896224976
1984	10.5997295379639
1985	9.89614963531494
1986	10.8862895965576
1987	10.4626598358154
1988	10.717080116272
1989	10.9613199234009
1990	11.1944799423218
1991	9.79650020599365
1992	9.82651996612549
1993	9.86944961547852
1994	9.30163955688477
1995	11.0581197738647
1996	10.8848495483398
1997	10.9213600158691
1998	10.9566402435303
1999	11.1273002624512
2000	10.9100303649902
2001	10.6852903366089
2002	10.4584798812866
2003	10.2315397262573
2004	10.0069398880005
2005	9.7863302230835
2006	9.56223011016846
2007	9.35019016265869
2008	9.07141971588135
2009	8.94388008117676
2010	8.73762035369873
2011	8.49820995330811
2012	8.27554035186768
2013	8.05735969543457
2014	7.90802001953125
2015	8.1216402053833
2016	8.67424011230469
2017	8.75053024291992
2018	8.56855010986328
2019	8.62858963012695
2020	8.14120006561279
2021	9.1315803527832
2022	9.13551998138428