Year	% of total primary
1970	7.85017013549805
1971	7.78493022918701
1972	7.5460901260376
1973	7.17569017410278
1974	6.81162977218628
1975	6.23734998703003
1976	5.93661022186279
1977	5.33867979049683
1978	4.94057989120483
1979	4.50520992279053
1980	4.36526012420654
1981	4.19835996627808
1982	4.19997978210449
1983	4.136390209198
1984	4.68680000305176
1985	4.45749998092651
1986	4.29457998275757
1987	4.42140007019043
1988	4.4094500541687
1989	4.64219999313354
1990	4.98015022277832
1991	4.8934497833252
1992	5.08319997787476
1993	5.18461990356445
1994	5.34393978118896
1995	5.18021011352539
1996	5.52030992507935
1997	5.48249006271362
1998	5.54680013656616
1999	5.69176006317139
2000	5.89210987091064
2001	6.16344022750854
2002	6.25292015075684
2003	6.34340000152588
2004	6.32083988189697
2005	6.5274600982666
2006	6.89107990264893
2007	7.2536997795105
2008	7.54768991470337
2009	7.83770990371704
2010	8.10803985595703
2011	8.12963962554932
2012	8.71529960632324
2013	9.11373996734619
2014	9.23544979095459
2015	9.62819004058838
2016	9.86007022857666
2017	10.0378398895264
2018	9.97270011901855
2019	10.0637502670288
2020	10.3745498657227
2021	9.76574993133545
2022	9.77567005157471