Year	% of total primary
1970	15.1087503433228
1971	14.4034795761108
1972	14.6219997406006
1980	11.8017597198486
1982	13.1158199310303
1983	13.4387798309326
1984	13.2653503417969
1985	13.3059997558594
1986	13.2824001312256
1987	12.9802598953247
1988	12.7434101104736
1989	13.2589702606201
1990	12.6206798553467
1991	13.3111295700073
1992	13.7889404296875
1993	14.6663799285889
1994	12.8784103393555
1995	14.6674003601074
1999	16.4468803405762
2000	16.0094299316406
2001	16.0094203948975
2002	15.5097904205322
2004	15.2709703445435
2005	15.2330598831177
2006	14.8585300445557
2007	14.9187202453613
2008	15.3794002532959
2010	15.5534296035767
2022	15.5768299102783