Year	Percent of Total
1960-01-01	3.11287297347608
1961-01-01	3.26121097708844
1962-01-01	3.37386599268747
1963-01-01	3.46298616007222
1964-01-01	3.54862026896903
1965-01-01	3.63823461253161
1966-01-01	3.72629625331343
1967-01-01	3.81145190269714
1968-01-01	3.89057738944065
1969-01-01	3.95819719127990
1970-01-01	4.01362857750411
1971-01-01	4.06084183908526
1972-01-01	4.10349396618536
1973-01-01	4.13728547261543
1974-01-01	4.15767608811820
1975-01-01	4.16378359564038
1976-01-01	4.17717088459491
1977-01-01	4.16914040173939
1978-01-01	4.14733728519287
1979-01-01	4.12052558648687
1980-01-01	4.09241508095153
1981-01-01	4.09264487909478
1982-01-01	4.08851202727411
1983-01-01	4.07726023889858
1984-01-01	4.05354614754226
1985-01-01	4.01586503167132
1986-01-01	3.99882658383729
1987-01-01	3.96656285955395
1988-01-01	3.92306372515608
1989-01-01	3.87299672128069
1990-01-01	3.81917573439357
1991-01-01	3.77409438872545
1992-01-01	3.72718078974929
1993-01-01	3.68006550838613
1994-01-01	3.63425174331956
1995-01-01	3.59109809209414
1996-01-01	3.56528741656690
1997-01-01	3.53873123944439
1998-01-01	3.51277700792014
1999-01-01	3.48910987406503
2000-01-01	3.46890164836067
2001-01-01	3.45009116699652
2002-01-01	3.43022472283603
2003-01-01	3.41021833235743
2004-01-01	3.39091939998805
2005-01-01	3.37280669373328
2006-01-01	3.37297266306572
2007-01-01	3.37119902327661
2008-01-01	3.36176696586085
2009-01-01	3.33598798875464
2010-01-01	3.29094964710673
2011-01-01	3.23953504285444
2012-01-01	3.17238188216821
2013-01-01	3.10846882720007
2014-01-01	3.07197492549866
2015-01-01	3.07380603903865
2016-01-01	3.11628991672941
2017-01-01	3.18566993927934