Year	Percent of Total
1960-01-01	3.26208731936260
1961-01-01	3.29016488346663
1962-01-01	3.30221206788674
1963-01-01	3.30513045267692
1964-01-01	3.30754801104466
1965-01-01	3.31325666667475
1966-01-01	3.35189348147660
1967-01-01	3.38442611425389
1968-01-01	3.41429457058465
1969-01-01	3.44504407348982
1970-01-01	3.47746949084630
1971-01-01	3.54020879421710
1972-01-01	3.59926122344392
1973-01-01	3.64402341043429
1974-01-01	3.66112244036712
1975-01-01	3.64559359642225
1976-01-01	3.62721875450652
1977-01-01	3.58370996143615
1978-01-01	3.52191157026460
1979-01-01	3.44861052470509
1980-01-01	3.36804009566626
1981-01-01	3.32252298847051
1982-01-01	3.27034634235671
1983-01-01	3.21628748139917
1984-01-01	3.16573000853094
1985-01-01	3.12179814269297
1986-01-01	3.10284270275074
1987-01-01	3.08500741095258
1988-01-01	3.06712823998769
1989-01-01	3.04744362638390
1990-01-01	3.02517546679854
1991-01-01	3.02739244394477
1992-01-01	3.02483405054540
1993-01-01	3.01918825825650
1994-01-01	3.01216626310417
1995-01-01	3.00463808124434
1996-01-01	3.00705877884910
1997-01-01	3.00453991237993
1998-01-01	2.99678076353431
1999-01-01	2.98365040689295
2000-01-01	2.96583848371065
2001-01-01	2.96449182617577
2002-01-01	2.95949619677572
2003-01-01	2.94994988466151
2004-01-01	2.93416889302402
2005-01-01	2.91236318984787
2006-01-01	2.90413780143375
2007-01-01	2.88994435028584
2008-01-01	2.87215707933236
2009-01-01	2.85282487277896
2010-01-01	2.83377553702692
2011-01-01	2.82543893015937
2012-01-01	2.81523256384771
2013-01-01	2.80914550170971
2014-01-01	2.81425434661361
2015-01-01	2.83405342094986
2016-01-01	2.87791091311508
2017-01-01	2.92949855685536