Year	% of total primary
1970	33.732780456543
1971	35.4533081054688
1972	30.7730598449707
1973	30.3647403717041
1974	28.8796691894531
1975	28.3770503997803
1976	28.1266193389893
1977	27.6163692474365
1978	26.5607299804688
1979	25.3136501312256
1980	25.5870399475098
1981	26.3810005187988
1982	25.9487590789795
1983	25.6719608306885
1984	25.3108291625977
1985	25.2483596801758
1986	25.2180805206299
1987	24.9246807098389
1988	24.5833301544189
1989	24.0741291046143
1990	23.3116493225098
1991	23.238260269165
1992	22.8357391357422
1993	22.515209197998
1994	22.2869701385498
1995	22.2924098968506
1996	22.3372592926025
1997	21.8540496826172
1998	21.4021606445312
1999	20.8912296295166
2000	20.2289791107178
2001	20.3367595672607
2002	19.9646606445312
2003	19.4770393371582
2004	19.5510807037354
2005	19.5436897277832
2006	18.9320507049561
2007	19.2310600280762
2008	19.7068099975586
2009	19.958309173584
2010	20.4692192077637
2011	23.4161701202393
2012	23.4316501617432
2013	22.5907096862793
2014	22.1728801727295
2015	21.4350700378418
2016	21.133150100708
2017	21.765230178833
2018	23.254810333252
2019	22.7790794372559
2020	22.4125995635986
2021	22.9395904541016
2022	23.0025405883789