Year	Percent of Total
1960-01-01	3.99635990897149
1961-01-01	3.95538148235370
1962-01-01	3.89108881241460
1963-01-01	3.81238323409431
1964-01-01	3.72952824586719
1965-01-01	3.64684540892964
1966-01-01	3.59036858802942
1967-01-01	3.53100923056556
1968-01-01	3.46891604586362
1969-01-01	3.40246565917061
1970-01-01	3.33198384200653
1971-01-01	3.29588667049062
1972-01-01	3.25337371680969
1973-01-01	3.20613494090739
1974-01-01	3.15650711221216
1975-01-01	3.10590343529492
1976-01-01	3.07977433787379
1977-01-01	3.05196268935665
1978-01-01	3.02321692602266
1979-01-01	2.99384744872584
1980-01-01	2.96472623761389
1981-01-01	2.94781575970477
1982-01-01	2.92970124690479
1983-01-01	2.91368807669541
1984-01-01	2.90379458992180
1985-01-01	2.90208169462519
1986-01-01	2.91989329235046
1987-01-01	2.94146072847353
1988-01-01	2.96613101840581
1989-01-01	2.99277079551050
1990-01-01	3.02127457512837
1991-01-01	3.05360368792761
1992-01-01	3.08521557266068
1993-01-01	3.11706572176530
1994-01-01	3.14939457107921
1995-01-01	3.18194036147384
1996-01-01	3.22628107649015
1997-01-01	3.26457213909894
1998-01-01	3.29659067529536
1999-01-01	3.32193396491479
2000-01-01	3.34054644830054
2001-01-01	3.33923404679661
2002-01-01	3.34025811596170
2003-01-01	3.34416367800526
2004-01-01	3.35184553086327
2005-01-01	3.36637931246529
2006-01-01	3.38455605840811
2007-01-01	3.40215759275572
2008-01-01	3.42034365499438
2009-01-01	3.44153508976012
2010-01-01	3.46925048268615
2011-01-01	3.57033766259412
2012-01-01	3.66926678961707
2013-01-01	3.77457053791479
2014-01-01	3.89630002254846
2015-01-01	4.04024299563165
2016-01-01	4.17887720936648
2017-01-01	4.34388469582813