Year	% of total primary
1970	16.4773998260498
1971	17.3540592193604
1972	15.4907703399658
1973	15.0613498687744
1974	14.3904495239258
1975	13.9331703186035
1976	13.3792295455933
1977	13.0586996078491
1978	12.7924404144287
1979	12.4611396789551
1980	12.6025495529175
1981	13.212610244751
1982	13.3487501144409
1983	13.1576499938965
1984	12.999719619751
1985	12.9141998291016
1986	12.5383195877075
1987	12.2694396972656
1988	11.8845901489258
1989	11.3373003005981
1990	11.1121501922607
1991	10.9235601425171
1992	10.9717102050781
1993	10.8066596984863
1994	10.6179304122925
1995	10.9129495620728
1996	10.754599571228
1997	10.4214096069336
1998	10.2140102386475
1999	10.0654497146606
2000	10.1014404296875
2001	10.1838397979736
2002	9.98262023925781
2003	9.60457038879395
2004	9.61944007873535
2005	9.68041038513184
2006	9.74112033843994
2007	9.97385025024414
2008	10.2208404541016
2009	10.7326698303223
2010	11.1872701644897
2011	12.3687000274658
2012	12.5154304504395
2013	12.4862298965454
2014	12.0806999206543
2015	12.0960702896118
2016	12.2802495956421
2017	13.0860900878906
2018	13.8314599990845
2019	13.6556701660156
2020	13.4432802200317
2021	13.8650503158569
2022	13.9611196517944