Year	Percent of Total
1960-01-01	9.35569869492639
1961-01-01	9.59659221836463
1962-01-01	9.83543934280988
1963-01-01	10.07830050420500
1964-01-01	10.33313791934800
1965-01-01	10.60456466641330
1966-01-01	10.92032829266330
1967-01-01	11.24019984533260
1968-01-01	11.55519349431690
1969-01-01	11.84879890363100
1970-01-01	12.11098149415500
1971-01-01	12.39413180309980
1972-01-01	12.61084128317830
1973-01-01	12.78178102255540
1974-01-01	12.94130413993790
1975-01-01	13.10430118973470
1976-01-01	13.31030753004750
1977-01-01	13.53608169301580
1978-01-01	13.71164429803870
1979-01-01	13.73387482870630
1980-01-01	13.55957342309420
1981-01-01	13.29702390128690
1982-01-01	12.85690070660680
1983-01-01	12.35257946282640
1984-01-01	11.94260857523480
1985-01-01	11.71314162594120
1986-01-01	11.80886655548160
1987-01-01	12.02052880535630
1988-01-01	12.28797387335370
1989-01-01	12.52421351429010
1990-01-01	12.68021052552180
1991-01-01	12.87277647570490
1992-01-01	13.01064064679560
1993-01-01	13.10454357826240
1994-01-01	13.16954087164450
1995-01-01	13.21744283124820
1996-01-01	13.38987128245110
1997-01-01	13.55149583700610
1998-01-01	13.68729251198820
1999-01-01	13.77412339320890
2000-01-01	13.80163298960100
2001-01-01	13.89920792148610
2002-01-01	13.92452078963840
2003-01-01	13.92201812686580
2004-01-01	13.95087628970690
2005-01-01	14.04359800416760
2006-01-01	14.22642287727820
2007-01-01	14.46159960434840
2008-01-01	14.74431478595990
2009-01-01	15.06969922793750
2010-01-01	15.43849512057660
2011-01-01	15.90552872321750
2012-01-01	16.41736301633500
2013-01-01	16.95475219597830
2014-01-01	17.48729964902670
2015-01-01	17.99453816485130
2016-01-01	18.53276620833180
2017-01-01	19.02690100291920