Year	Percent of Total
1960-01-01	2.37540758698685
1961-01-01	2.39190697528179
1962-01-01	2.39500034174014
1963-01-01	2.38660194336990
1964-01-01	2.36853368007684
1965-01-01	2.34211139594500
1966-01-01	2.36901062819707
1967-01-01	2.38625630831217
1968-01-01	2.39407467261200
1969-01-01	2.39280853692897
1970-01-01	2.38385518404494
1971-01-01	2.41548950005433
1972-01-01	2.43808876014169
1973-01-01	2.45292396118104
1974-01-01	2.46289944216164
1975-01-01	2.46933409148111
1976-01-01	2.51276684805358
1977-01-01	2.55223950865132
1978-01-01	2.58759885640472
1979-01-01	2.61659079053315
1980-01-01	2.63944449916698
1981-01-01	2.67847655324053
1982-01-01	2.70797549031671
1983-01-01	2.73192731408985
1984-01-01	2.75708875363637
1985-01-01	2.78875558423848
1986-01-01	2.85098824479422
1987-01-01	2.90079109164988
1988-01-01	2.93655229112878
1989-01-01	2.95309696109593
1990-01-01	2.94540613532504
1991-01-01	2.99684458373599
1992-01-01	3.03604684562292
1993-01-01	3.05922065663858
1994-01-01	3.05804852239447
1995-01-01	3.02288614031856
1996-01-01	3.01832940166002
1997-01-01	3.01992521419616
1998-01-01	3.02877781880644
1999-01-01	3.05194553482551
2000-01-01	3.09638824040864
2001-01-01	3.08966638717382
2002-01-01	3.07653329580853
2003-01-01	3.06010494080513
2004-01-01	3.04031527376469
2005-01-01	3.01508939878512
2006-01-01	3.03186942027432
2007-01-01	3.05047179962493
2008-01-01	3.06533482318967
2009-01-01	3.07231115710025
2010-01-01	3.07166059838531
2011-01-01	3.07301887121585
2012-01-01	3.06112809970817
2013-01-01	3.04412369575467
2014-01-01	3.03037963786034
2015-01-01	3.02354353844468
2016-01-01	3.03954009505783
2017-01-01	3.05699225639732