Year	% of total
1971	1.3008326369375398
1972	1.3585276724766582
1973	1.6426962836609695
1974	1.4072878206241797
1975	1.520373282972174
1976	1.7577910629662745
1977	1.7241235561729569
1978	1.7909038071984826
1979	1.4680085700592704
1980	1.3473036066391832
1981	1.5140819025751031
1982	1.5550792308175105
1983	1.6415418775972455
1984	0.6370045831418556
1985	0.658787637836621
1986	0.7309888546913802
1987	0.7958803629116549
1988	0.804456186974443
1989	0.7857752115636483
1990	0.9726179353622078
1991	0.9567350901908236
1992	0.9083472752992927
1993	0.9754383233910461
1994	1.0296087178050135
1995	1.1172324780889742
1996	1.2706044777943255
1997	1.3131331398214303
1998	1.627166858568358
1999	2.17515837163098
2000	2.4907857928252493
2001	2.577947532108453
2002	2.2977413693243465
2003	2.1082009412504368
2004	2.2078205159879674
2005	2.2742309316154454
2006	3.0581780825380154
2007	3.687433174859335
2008	3.8932689745908022
2009	4.611958359929975
2010	4.521020028626691
2011	4.774630311110906
2012	5.252568947336435
2013	4.966782095731608
2014	4.87036369426621
2015	4.81197768476229