Year	Percent of Total
1960-01-01	65.6154934274448
1961-01-01	65.2010183455766
1962-01-01	64.8118238891420
1963-01-01	64.4127236298004
1964-01-01	63.9757136452671
1965-01-01	63.5021172711117
1966-01-01	63.0032751923223
1967-01-01	62.5035976591592
1968-01-01	62.0393707762227
1969-01-01	61.6737613154947
1970-01-01	61.4445070200668
1971-01-01	61.2907498205379
1972-01-01	61.2876704052978
1973-01-01	61.4199694625983
1974-01-01	61.6538054545526
1975-01-01	61.9680769929229
1976-01-01	62.2843388782958
1977-01-01	62.6354926605850
1978-01-01	63.0595565486534
1979-01-01	63.6060354817690
1980-01-01	64.2834352551831
1981-01-01	64.9551785893456
1982-01-01	65.7307554240027
1983-01-01	66.5232427501301
1984-01-01	67.2162094979121
1985-01-01	67.7444704228622
1986-01-01	67.9756702375864
1987-01-01	68.1254640445944
1988-01-01	68.1958756156285
1989-01-01	68.1998035014828
1990-01-01	68.1482101966235
1991-01-01	67.9672098540777
1992-01-01	67.7016391278025
1993-01-01	67.4049294445093
1994-01-01	67.1791442756822
1995-01-01	67.0927636765451
1996-01-01	67.0603251764217
1997-01-01	67.1880282977105
1998-01-01	67.4178745313112
1999-01-01	67.6389463171117
2000-01-01	67.7829460784338
2001-01-01	67.8768837953466
2002-01-01	67.9004579556580
2003-01-01	67.8734889036641
2004-01-01	67.8431945263396
2005-01-01	67.8309232884845
2006-01-01	67.7483950904887
2007-01-01	67.6814830223551
2008-01-01	67.6245461838065
2009-01-01	67.5619991211509
2010-01-01	67.4849514545213
2011-01-01	67.4236961728936
2012-01-01	67.3535857972271
2013-01-01	67.2623179278746
2014-01-01	67.1553835069650
2015-01-01	67.0395546223339
2016-01-01	66.8762899389668
2017-01-01	66.7068553857482