Year	Percent of Total
1960-01-01	52.6061691155943
1961-01-01	52.3723782206081
1962-01-01	52.1245779407153
1963-01-01	51.9064826643157
1964-01-01	51.7813221707295
1965-01-01	51.7741204585086
1966-01-01	51.6933164976702
1967-01-01	51.7597748871257
1968-01-01	51.9246352162468
1969-01-01	52.1227129436023
1970-01-01	52.3245677700147
1971-01-01	52.5044625535479
1972-01-01	52.6891121017502
1973-01-01	52.8936750662901
1974-01-01	53.1455574572930
1975-01-01	53.4533499371054
1976-01-01	53.7192756970734
1977-01-01	54.0350914702476
1978-01-01	54.3866694688832
1979-01-01	54.7528826532922
1980-01-01	55.1214947553672
1981-01-01	55.4379100528059
1982-01-01	55.7622883868575
1983-01-01	56.0917943836251
1984-01-01	56.4302832554044
1985-01-01	56.7811045373455
1986-01-01	57.0925378189491
1987-01-01	57.4299848570292
1988-01-01	57.7835005212522
1989-01-01	58.1406041814518
1990-01-01	58.4963408906724
1991-01-01	58.8449451316310
1992-01-01	59.1911910971969
1993-01-01	59.5437743876734
1994-01-01	59.9138732891992
1995-01-01	60.3041480675108
1996-01-01	60.6608285835431
1997-01-01	61.0279417283621
1998-01-01	61.4023439024901
1999-01-01	61.7792348596293
2000-01-01	62.1561312444488
2001-01-01	62.5005805194664
2002-01-01	62.8566539118496
2003-01-01	63.2171371264381
2004-01-01	63.5735113613292
2005-01-01	63.9217332044472
2006-01-01	64.2960601128041
2007-01-01	64.6574944889708
2008-01-01	65.0085929807968
2009-01-01	65.3519856464876
2010-01-01	65.6846213793024
2011-01-01	65.9930866346338
2012-01-01	66.2816797568379
2013-01-01	66.5479926670049
2014-01-01	66.7881550942777
2015-01-01	66.9986221069814
2016-01-01	67.1439067152900
2017-01-01	67.2780608560654