Year	% of total primary
1970	16.0047798156738
1971	16.001579284668
1972	16.0610504150391
1973	15.9804401397705
1974	16.3665103912354
1975	16.456880569458
1976	16.4923896789551
1977	16.6443996429443
1978	16.7809906005859
1979	16.9559803009033
1980	17.1233806610107
1981	17.2263202667236
1982	17.265869140625
1983	17.2811603546143
1984	17.0755805969238
1985	16.8357791900635
1986	16.9425201416016
1987	16.9112091064453
1988	16.6038608551025
1989	16.5815391540527
1990	16.5768795013428
1991	16.544189453125
1992	16.4296798706055
1993	16.3630294799805
1994	16.6006107330322
1995	16.4989490509033
1996	16.8464908599854
1997	16.5262393951416
1998	16.1663799285889
1999	15.9252195358276
2000	15.6881904602051
2001	15.5894002914429
2002	15.4841604232788
2003	15.2723398208618
2004	15.0605602264404
2005	14.8526802062988
2006	14.5219602584839
2007	14.2209196090698
2008	14.0679502487183
2009	13.9113502502441
2010	13.7157497406006
2011	13.5163202285767
2012	13.646900177002
2013	13.6623201370239
2014	13.7315998077393
2015	13.7425403594971
2016	13.8479604721069
2017	13.8587703704834
2018	13.9068698883057
2019	13.978289604187
2020	14.0171403884888
2021	14.0481100082397
2022	14.008749961853