Year	Percent of Total
1960-01-01	6.04236880115551
1961-01-01	6.07547169811321
1962-01-01	6.06828549048519
1963-01-01	6.06591629035520
1964-01-01	6.07023154943153
1965-01-01	6.08483708201488
1966-01-01	6.04154476301931
1967-01-01	6.02690436275913
1968-01-01	6.02344562695047
1969-01-01	6.02996401189172
1970-01-01	6.03265539959897
1971-01-01	6.02156143519467
1972-01-01	6.01157327625302
1973-01-01	6.02939617708370
1974-01-01	6.06227516050743
1975-01-01	6.11008558482967
1976-01-01	6.19216848725046
1977-01-01	6.28960000000000
1978-01-01	6.39656845862425
1979-01-01	6.49394502171811
1980-01-01	6.57827254351827
1981-01-01	6.63169782162917
1982-01-01	6.66001642999648
1983-01-01	6.69288481910926
1984-01-01	6.73202896672857
1985-01-01	6.79735380033221
1986-01-01	6.78675504256900
1987-01-01	6.78721398577428
1988-01-01	6.77668238319760
1989-01-01	6.74327098540146
1990-01-01	6.69036021748980
1991-01-01	6.75944055944056
1992-01-01	6.81868192320387
1993-01-01	6.87859243867556
1994-01-01	6.95182207150521
1995-01-01	7.02580081613496
1996-01-01	7.16446733183135
1997-01-01	7.31592296613518
1998-01-01	7.47588018386624
1999-01-01	7.63013578843487
2000-01-01	7.77439587928676
2001-01-01	7.68587934647014
2002-01-01	7.55911309573293
2003-01-01	7.40658829007100
2004-01-01	7.23789492935851
2005-01-01	7.06301271071847
2006-01-01	7.08127460712254
2007-01-01	7.16208283027436
2008-01-01	7.30983834329445
2009-01-01	7.49610035810796
2010-01-01	7.68885728351841
2011-01-01	7.71174074961343
2012-01-01	7.73473478896896
2013-01-01	7.79604376650676
2014-01-01	7.94175048791473
2015-01-01	8.20443344498730
2016-01-01	8.38073608693807
2017-01-01	8.60593010122761