Year	Percent of Total
1960-01-01	58.5808882575415
1961-01-01	58.4546316683536
1962-01-01	58.4487108175792
1963-01-01	58.5479728164601
1964-01-01	58.7308543524475
1965-01-01	58.9915754168861
1966-01-01	59.4078783320932
1967-01-01	59.9469332067780
1968-01-01	60.5675200383127
1969-01-01	61.2179091972744
1970-01-01	61.8676069165440
1971-01-01	62.6321937231649
1972-01-01	63.3227851986224
1973-01-01	63.9753834591752
1974-01-01	64.6445668417681
1975-01-01	65.3438134022715
1976-01-01	65.8354843711385
1977-01-01	66.3890862570319
1978-01-01	66.9505251127234
1979-01-01	67.4418045240624
1980-01-01	67.8251121898625
1981-01-01	68.1030508521613
1982-01-01	68.2962961306417
1983-01-01	68.4062554848748
1984-01-01	68.4560998414144
1985-01-01	68.4586531418146
1986-01-01	68.4150193375478
1987-01-01	68.3479598578324
1988-01-01	68.2607794716920
1989-01-01	68.1582773082766
1990-01-01	68.0476681924610
1991-01-01	67.9222129203741
1992-01-01	67.7961552757065
1993-01-01	67.6941238090100
1994-01-01	67.6443871995868
1995-01-01	67.6570733390265
1996-01-01	67.6564266204742
1997-01-01	67.7477422947081
1998-01-01	67.9051892340328
1999-01-01	68.0870656760891
2000-01-01	68.2675948966697
2001-01-01	68.4889236110081
2002-01-01	68.6859622662690
2003-01-01	68.8679417092668
2004-01-01	69.0461800914865
2005-01-01	69.2107031780867
2006-01-01	69.3321033111993
2007-01-01	69.4282713846897
2008-01-01	69.4763539383919
2009-01-01	69.4533778520526
2010-01-01	69.3499963182645
2011-01-01	69.1172710943708
2012-01-01	68.8683738623618
2013-01-01	68.5820323895608
2014-01-01	68.2492504927997
2015-01-01	67.8743741708730
2016-01-01	67.4563931451634
2017-01-01	66.9906364368542