Year	% of total primary
1970	2.2744300365448
1971	1.55583000183105
1972	1.94293999671936
1973	2.61550998687744
1974	4.67270994186401
1975	5.02928018569946
1980	0.191410005092621
1981	0.213699996471405
1982	0.258199989795685
1983	0.232099995017052
1984	0.272650003433228
1985	0.303299993276596
1986	0.095830000936985
1987	0.0799399986863136
1988	0.0977199971675873
1989	0.17391000688076
1990	0.166850000619888
1991	0.141299992799759
1992	0.108450002968311
1993	0.101450003683567
1994	0.0955799967050552
1995	0.133330002427101
1996	0.144160002470016
1997	0.154070004820824
1998	0.182040005922318
1999	0.170389994978905
2001	0.11930999904871
2002	0.350589990615845
2003	0.47240999341011
2004	0.582149982452393
2005	0.856069982051849
2006	1.00750005245209
2007	0.979849994182587
2008	1.42008996009827
2009	1.5219099521637
2010	1.80868995189667
2011	2.75760006904602
2013	2.40511989593506
2014	2.77273011207581
2015	3.45918989181519
2017	3.78306007385254
2018	3.90006995201111
2019	4.06578016281128
2020	4.25695991516113
2021	4.54768991470337