Year	% of total
1971	47.11599293362364
1972	46.89181422743679
1973	47.977181899653154
1974	47.89745153964635
1975	47.898645251201415
1976	48.474099918542166
1977	48.2752184501426
1978	48.928082070008834
1979	48.930112690966126
1980	49.73754705809841
1981	51.342579430465236
1982	52.57811841091724
1983	52.2637175272934
1984	52.926142359090576
1985	52.20159517529874
1986	52.190178592523324
1987	52.90092884134751
1988	52.59569060880092
1989	50.544898376110886
1990	50.07072272505094
1991	50.4935534597248
1992	47.966506683768586
1993	49.28068471394845
1994	48.81161829993894
1995	49.44452460440491
1996	48.656466740513835
1997	48.60843975972821
1998	47.73347750822038
1999	47.92847166951634
2000	46.94725174290381
2001	47.435745950755724
2002	46.195218123360824
2003	47.271778540710926
2004	48.86205832936279
2005	48.60696669461216
2006	48.24439321411718
2007	49.55117155695212
2008	50.88856240081541
2009	49.88287297028588
2010	49.03532859383291
2011	48.30386238835796
2012	47.572412988043624
2013	46.895180232302316
2014	49.304292087898055