Year	% of total
1971	0.8168779803894849
1972	0.6956499764758478
1973	0.6543272595655131
1974	0.5842750872748315
1975	0.5353622481281123
1976	0.5059192383790638
1977	0.4599498399486695
1978	0.4562453411495068
1979	0.40287651726582513
1980	0.38863990650778196
1981	0.38781044716591273
1982	0.3647074929944698
1983	0.35196865002120437
1984	0.3398089415624693
1985	0.3212314476072732
1986	0.8614612181119193
1987	0.858535416231865
1988	0.7870131644076754
1989	0.7742157243202451
1990	0.7720855891616628
1991	0.7547483593507353
1992	0.6946401880415858
1993	0.6768335726473461
1994	0.5202637894299481
1995	0.6419143427295461
1996	0.6378317845177813
1997	0.596060842934779
1998	0.5848434233048632
1999	0.5502823903915984
2000	0.590693074689852
2001	0.6108715659355234
2002	0.4819148801524922
2003	0.8659996306037973
2004	1.0421901194899543
2005	1.02041434615195
2006	1.432543772038968
2007	1.0022759159840113
2008	1.0880875309494684
2009	1.2064062573681595
2010	1.1146682424159466
2011	1.0845341202041119
2012	1.151047875548556
2013	1.237923609235443
2014	2.025788508103823
2015	2.1617560236411455