Year	% of total primary
1970	8.65223979949951
1971	9.06709957122803
1972	8.90641021728516
1973	8.75992965698242
1974	8.31809043884277
1975	7.7948899269104
1976	7.71906995773315
1977	7.72294998168945
1978	7.73695993423462
1979	7.72415018081665
1980	7.75391006469727
1981	7.82560014724731
1982	7.94197988510132
1983	8.05370998382568
1984	8.15219974517822
1985	8.17965030670166
1986	8.2096996307373
1987	8.24606990814209
1988	8.38951969146729
1989	8.51439952850342
1990	8.63169956207275
1991	8.7212495803833
1992	8.88278007507324
1993	9.02262020111084
1994	9.16434955596924
1995	9.30692005157471
1996	9.41678047180176
1997	9.52025032043457
1998	9.64857006072998
1999	9.83699989318848
2000	9.99705982208252
2001	10.2633199691772
2002	10.3391895294189
2003	11.1190299987793
2004	11.5442895889282
2005	12.2959403991699
2006	12.8333101272583
2007	13.4915399551392
2008	13.92506980896
2009	14.5932197570801
2010	15.1672801971436
2011	15.8714199066162
2012	16.400239944458
2013	16.8505001068115
2014	17.2273597717285
2015	17.3597297668457
2016	17.27712059021
2017	17.7295093536377
2018	19.0772094726562
2019	19.0335292816162
2020	19.3053703308105
2021	19.2480907440186
2022	19.584939956665