Year	Percent
1960-01-01	42.0155351385692
1961-01-01	42.5240655852853
1962-01-01	42.6589582741732
1963-01-01	43.2091693201440
1964-01-01	43.6048516840665
1965-01-01	44.2915397215103
1966-01-01	45.5648539757450
1967-01-01	46.6064595930640
1968-01-01	47.2113123972289
1969-01-01	48.4676301499768
1970-01-01	49.2759554317336
1971-01-01	49.3713159953652
1972-01-01	50.1401344052450
1973-01-01	51.2475522864212
1974-01-01	52.5390410190247
1975-01-01	53.4290191967643
1976-01-01	54.6602580467755
1977-01-01	56.0436627178421
1978-01-01	57.8899576166466
1979-01-01	59.1457637835303
1980-01-01	59.9165959495117
1981-01-01	60.7422559220233
1982-01-01	61.4909525517367
1983-01-01	61.9448710530154
1984-01-01	62.9187165400565
1985-01-01	64.1106410020642
1986-01-01	65.1243780069874
1987-01-01	66.0597660698850
1988-01-01	66.7686493574879
1989-01-01	67.7505178739300
1990-01-01	67.8352311660764
1991-01-01	67.7479778728648
1992-01-01	68.4072342774187
1993-01-01	68.5915325409376
1994-01-01	69.4434771691408
1995-01-01	69.7217302774918
1996-01-01	70.1181761385180
1997-01-01	70.7098915017890
1998-01-01	70.7064074197071
1999-01-01	70.7321394755193
2000-01-01	70.7145766602532
2001-01-01	70.4038013610422
2002-01-01	70.0539662557588
2003-01-01	69.6742032728560
2004-01-01	69.1699118991180
2005-01-01	69.1772131413977
2006-01-01	69.2974379313884
2007-01-01	69.0690110287944
2008-01-01	69.2945430631854
2009-01-01	69.0269907430662
2010-01-01	68.3959149641292
2011-01-01	67.8112543823848
2012-01-01	67.5800876339423
2013-01-01	67.1646845192095
2014-01-01	67.1165368524256
2015-01-01	66.9369592359625
2016-01-01	67.3045285758228
2017-01-01	67.8902738889893