Year	Percent of Total
1960-01-01	3.15877856618134
1961-01-01	3.17742197162311
1962-01-01	3.18311294590608
1963-01-01	3.17861417887668
1964-01-01	3.16768774584473
1965-01-01	3.15209515269485
1966-01-01	3.17309374210844
1967-01-01	3.18753920357400
1968-01-01	3.19529279126060
1969-01-01	3.19573230110918
1970-01-01	3.18931206988994
1971-01-01	3.21079205561831
1972-01-01	3.22515172357090
1973-01-01	3.23246576027376
1974-01-01	3.23256976107727
1975-01-01	3.22580796802442
1976-01-01	3.23943681978137
1977-01-01	3.24448225664866
1978-01-01	3.24307152412380
1979-01-01	3.23797651040937
1980-01-01	3.23117745884686
1981-01-01	3.24709433926884
1982-01-01	3.25704721327488
1983-01-01	3.26118419850590
1984-01-01	3.25915159868206
1985-01-01	3.25104929724533
1986-01-01	3.26954145895727
1987-01-01	3.28173729910301
1988-01-01	3.28815546085761
1989-01-01	3.28900670710601
1990-01-01	3.27548737760819
1991-01-01	3.29322735873003
1992-01-01	3.30608433794041
1993-01-01	3.31548669952824
1994-01-01	3.32325186480595
1995-01-01	3.33084351103181
1996-01-01	3.33976567149835
1997-01-01	3.34344599684054
1998-01-01	3.34252620402089
1999-01-01	3.33646629043506
2000-01-01	3.32531181112798
2001-01-01	3.32635017274124
2002-01-01	3.32200048496874
2003-01-01	3.31365012853110
2004-01-01	3.30279253621540
2005-01-01	3.29070144270761
2006-01-01	3.30127629565232
2007-01-01	3.30887186885146
2008-01-01	3.31372525286369
2009-01-01	3.31573075211657
2010-01-01	3.31566482612258
2011-01-01	3.32999341521767
2012-01-01	3.34007163818752
2013-01-01	3.34993136511423
2014-01-01	3.36470578592726
2015-01-01	3.38723505869417
2016-01-01	3.42943186036672
2017-01-01	3.47532646261134