Year	% of total primary
1974	0.154039993882179
1975	0.155249997973442
1976	0.155609995126724
1977	0.154620006680489
1978	0.150720000267029
1979	0.147799998521805
1980	0.142110005021095
1981	0.139740005135536
1982	0.13748000562191
1983	0.130319997668266
1984	0.115709997713566
1985	0.120010003447533
1986	0.136999994516373
1987	0.161990001797676
1988	0.182339996099472
1989	0.197640001773834
1990	0.208409994840622
1991	0.207399994134903
1992	0.205860003829002
1993	0.236430004239082
1994	0.26078000664711
1995	0.291790008544922
1996	0.332100003957748
1997	0.380870014429092
1998	0.445450007915497
1999	0.501389980316162
2000	0.569649994373322
2001	0.646650016307831
2002	0.710609972476959
2003	0.773720026016235
2004	0.836589992046356
2005	0.928399980068207
2006	1.04733002185822
2007	1.13429999351501
2008	1.20848000049591
2009	1.25238001346588
2010	1.2946799993515
2011	1.36509001255035
2012	1.40073001384735
2013	1.4757000207901
2014	1.55118000507355
2015	1.67525994777679
2016	1.80713999271393
2017	1.73926997184753
2018	1.83940005302429
2019	2.00296998023987
2020	2.13775992393494
2021	2.12657999992371
2022	2.1497700214386