Year	Percent of Total
1960-01-01	2.58991845316898
1961-01-01	2.57606930157011
1962-01-01	2.55851187090522
1963-01-01	2.53115264797508
1964-01-01	2.50164647654020
1965-01-01	2.45119981316778
1966-01-01	2.44890198688088
1967-01-01	2.43169856236865
1968-01-01	2.41089860766286
1969-01-01	2.39589528721449
1970-01-01	2.38407850183125
1971-01-01	2.38234850642497
1972-01-01	2.38818544891892
1973-01-01	2.39375229867518
1974-01-01	2.39721623359431
1975-01-01	2.40332847442481
1976-01-01	2.44765933245655
1977-01-01	2.49005085120495
1978-01-01	2.53270827176746
1979-01-01	2.56411928076878
1980-01-01	2.59052309246456
1981-01-01	2.61994083020709
1982-01-01	2.63473758531419
1983-01-01	2.64351652339586
1984-01-01	2.64986089323487
1985-01-01	2.66456440462568
1986-01-01	2.68796121350398
1987-01-01	2.71902877060318
1988-01-01	2.75245968030112
1989-01-01	2.78030425448418
1990-01-01	2.80491902425912
1991-01-01	2.84260556943513
1992-01-01	2.87522757102333
1993-01-01	2.91059519341414
1994-01-01	2.95814163174780
1995-01-01	3.02815626451303
1996-01-01	3.14005097810872
1997-01-01	3.26137546116734
1998-01-01	3.39479803570500
1999-01-01	3.53536089535273
2000-01-01	3.68030986076238
2001-01-01	3.81845610343278
2002-01-01	3.95085971713081
2003-01-01	4.07631804479681
2004-01-01	4.18718973787381
2005-01-01	4.28025693459961
2006-01-01	4.35835794862709
2007-01-01	4.41991251822537
2008-01-01	4.46335935824538
2009-01-01	4.48122854378408
2010-01-01	4.47421339822392
2011-01-01	4.40832669120920
2012-01-01	4.32363290808202
2013-01-01	4.23556292573925
2014-01-01	4.15777703204188
2015-01-01	4.10274304916552
2016-01-01	4.10257249459972
2017-01-01	4.11981756927096