Year	Percent of Total
1960-01-01	3.36372461001843
1961-01-01	3.40984084784620
1962-01-01	3.45072624106301
1963-01-01	3.48854121661769
1964-01-01	3.52701416078375
1965-01-01	3.56737885401495
1966-01-01	3.61078574232557
1967-01-01	3.65337733153992
1968-01-01	3.69151695220636
1969-01-01	3.71871787273076
1970-01-01	3.73214335513985
1971-01-01	3.74427732125581
1972-01-01	3.74103131158787
1973-01-01	3.73053963291263
1974-01-01	3.72430410928288
1975-01-01	3.72836956861188
1976-01-01	3.74183039751220
1977-01-01	3.77004222989617
1978-01-01	3.80310792233883
1979-01-01	3.82738133681281
1980-01-01	3.83791028229735
1981-01-01	3.86171606611121
1982-01-01	3.86924379070907
1983-01-01	3.87272329704611
1984-01-01	3.88788133850343
1985-01-01	3.92183075576080
1986-01-01	3.97511342527709
1987-01-01	4.04007043111856
1988-01-01	4.11376679030152
1989-01-01	4.19093116695139
1990-01-01	4.26908242817763
1991-01-01	4.34259715163784
1992-01-01	4.41687453020327
1993-01-01	4.49139365782200
1994-01-01	4.56599344658809
1995-01-01	4.64092841620976
1996-01-01	4.72677337045196
1997-01-01	4.81110026209544
1998-01-01	4.89276134526899
1999-01-01	4.97003910615511
2000-01-01	5.04287405642761
2001-01-01	5.10874239674694
2002-01-01	5.16928424201218
2003-01-01	5.23028522037860
2004-01-01	5.29876826784523
2005-01-01	5.37886711426265
2006-01-01	5.47026062058538
2007-01-01	5.57259533497276
2008-01-01	5.68174838744648
2009-01-01	5.79138894042095
2010-01-01	5.89955291192067
2011-01-01	5.99993112772836
2012-01-01	6.09570735771378
2013-01-01	6.19873255337786
2014-01-01	6.32456191193802
2015-01-01	6.48177654137789
2016-01-01	6.65633514481914
2017-01-01	6.85734233002885