Year	Percent
1960-01-01	58.3334304543312
1961-01-01	58.1783008030189
1962-01-01	58.8720729923885
1963-01-01	59.4540922083989
1964-01-01	59.6199936148064
1965-01-01	59.9480745051493
1966-01-01	60.6164827054064
1967-01-01	60.8571222875313
1968-01-01	60.9956360603377
1969-01-01	60.8945131309504
1970-01-01	60.1293189575674
1971-01-01	59.2373516160654
1972-01-01	58.1034098473188
1973-01-01	56.8728247571633
1974-01-01	56.1742311281772
1975-01-01	54.5582272249433
1976-01-01	54.0610186775156
1977-01-01	54.1255009825274
1978-01-01	54.6049194332695
1979-01-01	54.6199035202518
1980-01-01	53.8383580047728
1981-01-01	52.9733861243901
1982-01-01	52.0981070894316
1983-01-01	51.4235751432440
1984-01-01	51.6702892265637
1985-01-01	51.8247865470384
1986-01-01	51.8147523089334
1987-01-01	52.5075603529851
1988-01-01	52.8298033602729
1989-01-01	53.7527636627727
1990-01-01	54.0009444424512
1991-01-01	53.2081887772142
1992-01-01	53.3776797937542
1993-01-01	53.7473398995007
1994-01-01	54.4118904918436
1995-01-01	55.1460050975285
1996-01-01	55.9246164901745
1997-01-01	57.1722259972068
1998-01-01	57.7320773306372
1999-01-01	57.7304203499637
2000-01-01	57.7858718750680
2001-01-01	58.5519574289380
2002-01-01	59.4902064843879
2003-01-01	59.8592940658239
2004-01-01	59.9296288175851
2005-01-01	60.8255690358359
2006-01-01	61.7965810848958
2007-01-01	61.8057740403953
2008-01-01	62.1436831195627
2009-01-01	60.6291452555756
2010-01-01	60.2940406086480
2011-01-01	59.9801942552530
2012-01-01	60.6477064280463
2013-01-01	60.9303967739597
2014-01-01	61.3478116207025
2015-01-01	61.5241698377851
2016-01-01	61.7894598432369
2017-01-01	62.5177462610059