Year	% of total
1971	1.7926006266570256
1972	1.606727551194055
1973	3.2913896367932303
1974	2.876966013719711
1975	3.0561180550706424
1976	3.4011399884955287
1977	2.296619763868672
1978	2.5152321368576853
1979	2.550057170207674
1980	2.492338612562184
1981	2.2829290410337792
1982	1.4291570659165123
1983	2.333739181940834
1984	2.370826327517294
1985	2.677256752254334
1986	2.462114712385584
1987	2.269183274294007
1988	2.380893909626719
1989	1.7015061548536152
1990	2.0978232649659074
1991	1.7305861127120556
1992	1.9947743200239634
1993	1.49593315689562
1994	1.4451924577739226
1995	1.884057971014493
1996	2.0474865190020566
1997	2.1331646490845775
1998	2.366645426014043
1999	2.427579383256683
2000	2.9668871382230275
2001	3.311111904531165
2002	3.1760747712538206
2003	2.7318668115057996
2004	2.4870210280544627
2005	2.420716098237142
2006	2.429877071637563
2007	2.058980308731694
2008	1.759522841263386
2009	2.0316100913330617
2010	2.6818022168312545
2011	3.0047387895798745
2012	2.9264974190796664
2013	2.8740033183537204
2014	2.7906394307101743