Year	% of total primary
1973	11.7093496322632
1974	11.9427499771118
1975	11.5190896987915
1984	3.64375996589661
1986	4.01945018768311
1991	4.01993989944458
1992	4.53795003890991
1994	4.51567983627319
1999	24.2527408599854
2000	26.2952308654785
2001	26.9641304016113
2002	27.1849994659424
2003	28.3269596099854
2004	29.558349609375
2005	30.0815601348877
2006	31.4407501220703
2007	31.9217891693115
2008	34.6039009094238
2009	34.9653701782227
2010	35.1069107055664
2011	34.7382583618164
2012	35.3757400512695
2014	36.7771301269531
2015	36.7485084533691
2016	38.1128005981445
2019	40.7714805603027
2020	40.8084106445312
2021	41.1917915344238
2022	40.8824996948242