Year	% of total primary
1970	16.5030307769775
1971	17.3798503875732
1972	15.516770362854
1973	15.0864696502686
1974	14.4137496948242
1975	13.9508600234985
1976	13.3917598724365
1977	13.0666799545288
1978	12.7964200973511
1979	12.4616298675537
1980	12.6001100540161
1981	13.2101602554321
1982	13.3463802337646
1983	13.1554098129272
1984	12.997579574585
1985	12.9120502471924
1986	12.5361795425415
1987	12.2674102783203
1988	11.8826704025269
1989	11.3358001708984
1990	11.1106300354004
1991	10.9220600128174
1992	10.9703798294067
1993	10.8054103851318
1994	10.6167802810669
1995	10.9118604660034
1996	10.7535600662231
1997	10.4205598831177
1998	10.2132501602173
1999	10.064829826355
2000	10.1007995605469
2001	10.1831903457642
2002	9.98206043243408
2003	9.60412979125977
2004	9.61907005310059
2005	9.68006992340088
2006	9.74083042144775
2007	9.97358989715576
2008	10.2206802368164
2009	10.7325096130371
2010	11.1871204376221
2011	12.3684902191162
2012	12.5152797698975
2013	12.486120223999
2014	12.0806198120117
2015	12.096019744873
2016	12.280179977417
2017	13.0859899520874
2018	13.8313398361206
2019	13.6556301116943
2020	13.4432897567749
2021	13.8650903701782
2022	13.9611701965332