Year	Percent of Total
1960-01-01	3.41604041337413
1961-01-01	3.43983368302053
1962-01-01	3.47358019370616
1963-01-01	3.50541811393939
1964-01-01	3.51841798844681
1965-01-01	3.50689282909362
1966-01-01	3.51523397401847
1967-01-01	3.49922656460334
1968-01-01	3.47485946210310
1969-01-01	3.46204959075123
1970-01-01	3.46896863435216
1971-01-01	3.52562510908691
1972-01-01	3.59017894209402
1973-01-01	3.65705159126374
1974-01-01	3.71975112916997
1975-01-01	3.77657223980881
1976-01-01	3.85025068338609
1977-01-01	3.92561891156867
1978-01-01	3.99899994053701
1979-01-01	4.06404522896827
1980-01-01	4.11846396245151
1981-01-01	4.19942890402709
1982-01-01	4.26160130241431
1983-01-01	4.31792856635426
1984-01-01	4.38767346260401
1985-01-01	4.48100740802747
1986-01-01	4.60943637087881
1987-01-01	4.76670015204541
1988-01-01	4.93780075591410
1989-01-01	5.09712176245104
1990-01-01	5.23167566690323
1991-01-01	5.40001047994240
1992-01-01	5.53535037883452
1993-01-01	5.65808621533360
1994-01-01	5.79937908643633
1995-01-01	5.97585210725336
1996-01-01	6.15953573021836
1997-01-01	6.38087195258518
1998-01-01	6.63294375016326
1999-01-01	6.90228454138621
2000-01-01	7.18283583664413
2001-01-01	7.50818627492487
2002-01-01	7.84458449622085
2003-01-01	8.18612425485900
2004-01-01	8.52664836257549
2005-01-01	8.86233668840161
2006-01-01	9.22382873227776
2007-01-01	9.57477054387177
2008-01-01	9.92871957843097
2009-01-01	10.30209111494860
2010-01-01	10.70500983243040
2011-01-01	11.10339101932530
2012-01-01	11.53686909440950
2013-01-01	11.99871227873050
2014-01-01	12.47632655070220
2015-01-01	12.96546591152070
2016-01-01	13.43642873583890
2017-01-01	13.91412753922880