Year	Percent of Total
1960-01-01	4.02692693191889
1961-01-01	4.06264843376790
1962-01-01	4.06013721318759
1963-01-01	4.03272658818534
1964-01-01	3.99970022984329
1965-01-01	3.96676779291116
1966-01-01	4.02690139665454
1967-01-01	4.09253013613994
1968-01-01	4.15778968030708
1969-01-01	4.21593752850352
1970-01-01	4.26638016618042
1971-01-01	4.33985608071436
1972-01-01	4.40716726652048
1973-01-01	4.47125137983673
1974-01-01	4.53821378816257
1975-01-01	4.61169442444378
1976-01-01	4.71318269675399
1977-01-01	4.81703863158045
1978-01-01	4.91760440883428
1979-01-01	5.00581757737916
1980-01-01	5.07782805274054
1981-01-01	5.15865007485638
1982-01-01	5.21784481165795
1983-01-01	5.26385906638894
1984-01-01	5.30595473426382
1985-01-01	5.34794907922030
1986-01-01	5.39913165812480
1987-01-01	5.44450114011936
1988-01-01	5.49115910821718
1989-01-01	5.54939868414342
1990-01-01	5.62598928043477
1991-01-01	5.71722730897962
1992-01-01	5.83140808436323
1993-01-01	5.95759682724436
1994-01-01	6.07912030762063
1995-01-01	6.18886272519348
1996-01-01	6.33167948447173
1997-01-01	6.44789333921613
1998-01-01	6.55159831219950
1999-01-01	6.66115165141391
2000-01-01	6.78430171116322
2001-01-01	6.93354339509729
2002-01-01	7.09231131019252
2003-01-01	7.25168346975254
2004-01-01	7.39185463856735
2005-01-01	7.50476991647762
2006-01-01	7.61069437359996
2007-01-01	7.69880749460601
2008-01-01	7.78204616091368
2009-01-01	7.87776699784397
2010-01-01	7.99596224597232
2011-01-01	8.14208801996606
2012-01-01	8.29557655161687
2013-01-01	8.47044711005933
2014-01-01	8.68807869266236
2015-01-01	8.96116238856862
2016-01-01	9.29502956883100
2017-01-01	9.68107526051532