Year	% of total primary
1970	11.1424102783203
1971	10.8456296920776
1972	10.9822597503662
1973	10.6489295959473
1974	10.1399002075195
1975	9.88669013977051
1976	9.44931030273438
1977	8.83421039581299
1978	7.98985004425049
1979	7.3514199256897
1980	7.87346982955933
1981	9.0285701751709
1982	9.35352039337158
1983	9.41965007781982
1984	9.55045032501221
1985	9.83172988891602
1986	9.83080959320068
1987	9.77931022644043
1988	9.54640007019043
1989	9.25115966796875
1990	9.17413997650146
1991	9.41891002655029
1992	9.53971004486084
1993	9.59294986724854
1994	9.60735988616943
1995	10.4031400680542
1996	10.1481599807739
1997	9.70232963562012
1998	9.35266971588135
1999	9.21749019622803
2000	9.23392009735107
2001	9.22813034057617
2002	8.94005012512207
2003	8.59111976623535
2004	8.42444038391113
2005	8.3767204284668
2006	8.57882976531982
2007	8.64229965209961
2008	8.99942970275879
2009	9.27758026123047
2010	9.48635005950928
2011	9.37417984008789
2012	9.73993015289307
2013	9.49549007415771
2014	9.12814998626709
2015	8.88869953155518
2016	9.16423034667969
2017	9.35208988189697
2018	9.53666973114014
2019	9.26525974273682
2020	9.00197982788086
2021	9.13694000244141
2022	9.13646030426025