Year	Percent of Total
1960-01-01	44.9945794885301
1961-01-01	45.2019323810777
1962-01-01	45.3612707753918
1963-01-01	45.4828283151562
1964-01-01	45.5746558617045
1965-01-01	45.6429615316684
1966-01-01	45.8518525723054
1967-01-01	46.0076012644285
1968-01-01	46.1249668044283
1969-01-01	46.2178270736287
1970-01-01	46.2935214993629
1971-01-01	46.4875489950922
1972-01-01	46.6321391297122
1973-01-01	46.7390213934752
1974-01-01	46.8186794838949
1975-01-01	46.8779044369978
1976-01-01	47.0176390380753
1977-01-01	47.1063724503006
1978-01-01	47.1487750085656
1979-01-01	47.1430378274203
1980-01-01	47.0872174248463
1981-01-01	47.1106262148747
1982-01-01	47.0628627300238
1983-01-01	46.9552630941790
1984-01-01	46.7963844996540
1985-01-01	46.5893194536468
1986-01-01	46.4532099683232
1987-01-01	46.2588813264486
1988-01-01	46.0211925813403
1989-01-01	45.7662607623721
1990-01-01	45.5169278310706
1991-01-01	45.2481223339655
1992-01-01	44.9984554046001
1993-01-01	44.7546023935015
1994-01-01	44.4886035715869
1995-01-01	44.1813516383406
1996-01-01	44.1720732391707
1997-01-01	44.1006694450248
1998-01-01	43.9922722835220
1999-01-01	43.8874715949259
2000-01-01	43.8068096644708
2001-01-01	43.7544169342607
2002-01-01	43.7148785206470
2003-01-01	43.6708026078593
2004-01-01	43.5901456224853
2005-01-01	43.4566555794636
2006-01-01	43.4447565265790
2007-01-01	43.3857003631004
2008-01-01	43.2855266387130
2009-01-01	43.1577588513305
2010-01-01	43.0082618305615
2011-01-01	42.7668914378846
2012-01-01	42.4872698650788
2013-01-01	42.1756786541560
2014-01-01	41.8395023593382
2015-01-01	41.4876338507521
2016-01-01	41.1638111163878
2017-01-01	40.8224318110552