Year	Percent of Total
1960-01-01	58.9935430972635
1961-01-01	58.9236076640524
1962-01-01	58.8178038405153
1963-01-01	58.6892497526337
1964-01-01	58.5917655426230
1965-01-01	58.5614035087719
1966-01-01	58.5050060841534
1967-01-01	58.5379563031508
1968-01-01	58.6204099017331
1969-01-01	58.6577445384767
1970-01-01	58.6086741863203
1971-01-01	58.3019211508695
1972-01-01	57.9698044945384
1973-01-01	57.7047628537266
1974-01-01	57.6327979497302
1975-01-01	57.8148989743905
1976-01-01	57.4729263402673
1977-01-01	57.5025278794183
1978-01-01	57.7478344562079
1979-01-01	58.0162510507145
1980-01-01	58.2283800914954
1981-01-01	58.5517077637961
1982-01-01	58.6961754479808
1983-01-01	58.8236457749497
1984-01-01	59.1363725043897
1985-01-01	59.6927850649434
1986-01-01	60.2079424936676
1987-01-01	60.9442246933851
1988-01-01	61.7932030045754
1989-01-01	62.5693088637251
1990-01-01	63.1744479848280
1991-01-01	63.7813566356175
1992-01-01	64.2010984368399
1993-01-01	64.4795820156744
1994-01-01	64.7103036550273
1995-01-01	64.9455780886270
1996-01-01	64.9065650356528
1997-01-01	64.9440452645019
1998-01-01	65.0161622098149
1999-01-01	65.0775234679886
2000-01-01	65.1215994663435
2001-01-01	65.2142462218946
2002-01-01	65.2839593284122
2003-01-01	65.3702238852399
2004-01-01	65.5142583765504
2005-01-01	65.7263436562578
2006-01-01	65.8992957895405
2007-01-01	66.0944742201067
2008-01-01	66.2991312052374
2009-01-01	66.4722548936394
2010-01-01	66.5774367921860
2011-01-01	66.8220390564563
2012-01-01	67.0134546510502
2013-01-01	67.1608964103113
2014-01-01	67.2926624406302
2015-01-01	67.4262610046415
2016-01-01	67.4600351331429
2017-01-01	67.5271035818356