Year	% of total primary
1970	23.1609401702881
1971	21.7525596618652
1972	21.2899608612061
1973	20.379430770874
1974	19.8507900238037
1975	19.5171604156494
1976	18.6298007965088
1977	18.2130508422852
1978	16.9787101745605
1979	15.9597797393799
1980	14.9916696548462
1981	14.0169897079468
1982	12.8659000396729
1983	11.7425498962402
1984	11.2255001068115
1985	11.2480697631836
1986	11.2057399749756
1987	11.3929300308228
1988	11.3845996856689
1989	11.2902698516846
1990	11.3388500213623
1991	10.3508100509644
1992	9.58209037780762
1993	10.0452003479004
1994	10.0803298950195
1995	11.8188400268555
1996	11.9252901077271
1997	11.2626104354858
1998	11.8192901611328
1999	11.6346397399902
2000	11.6418504714966
2001	11.3236799240112
2002	10.9105195999146
2006	11.7115497589111
2007	11.7098302841187
2008	9.67210006713867
2009	10.6673002243042
2011	14.1663799285889
2012	12.2564401626587
2013	13.0429496765137
2014	13.5113000869751
2015	13.3144397735596
2016	12.9714002609253
2017	13.8550901412964
2018	14.4805097579956
2019	15.6327199935913
2020	16.9715900421143
2021	17.8539199829102
2022	18.1267604827881