Year	Percent of Total
1960-01-01	53.8933687872208
1961-01-01	53.6768724895476
1962-01-01	53.4486636306802
1963-01-01	53.2467852678281
1964-01-01	53.1279570967459
1965-01-01	53.1157588147536
1966-01-01	53.0306509759178
1967-01-01	53.0809652786613
1968-01-01	53.2221670132382
1969-01-01	53.3942309109185
1970-01-01	53.5695209292795
1971-01-01	53.7259917383614
1972-01-01	53.8871980457045
1973-01-01	54.0655965375515
1974-01-01	54.2845336391496
1975-01-01	54.5510951705050
1976-01-01	54.7659690290108
1977-01-01	55.0212929148446
1978-01-01	55.3075409975425
1979-01-01	55.6100026470165
1980-01-01	55.9198398046581
1981-01-01	56.1789282459098
1982-01-01	56.4575318350546
1983-01-01	56.7479522244669
1984-01-01	57.0466451872405
1985-01-01	57.3536374413609
1986-01-01	57.6324738682574
1987-01-01	57.9267618287399
1988-01-01	58.2337143230268
1989-01-01	58.5503782149477
1990-01-01	58.8753892888647
1991-01-01	59.1882309287043
1992-01-01	59.5103122531395
1993-01-01	59.8449661995174
1994-01-01	60.1956902247505
1995-01-01	60.5621191549782
1996-01-01	60.8948671615917
1997-01-01	61.2365710792148
1998-01-01	61.5850626509415
1999-01-01	61.9377151388879
2000-01-01	62.2927137040885
2001-01-01	62.6214659268468
2002-01-01	62.9600740668777
2003-01-01	63.3027612318504
2004-01-01	63.6423992676524
2005-01-01	63.9749433018487
2006-01-01	64.3235221589126
2007-01-01	64.6628388742266
2008-01-01	64.9933454632585
2009-01-01	65.3147021142456
2010-01-01	65.6227599718666
2011-01-01	65.9040492511945
2012-01-01	66.1652742880016
2013-01-01	66.4047747249788
2014-01-01	66.6202585459305
2015-01-01	66.8090494897605
2016-01-01	66.9364151927184
2017-01-01	67.0541512535229