Year	Percent of Total
1960-01-01	3.97558297366134
1961-01-01	3.90265966060430
1962-01-01	3.79511291845182
1963-01-01	3.67098078545617
1964-01-01	3.55544689298707
1965-01-01	3.45685627689680
1966-01-01	3.40848631577920
1967-01-01	3.36805895564112
1968-01-01	3.32652720485630
1969-01-01	3.26776913484947
1970-01-01	3.18920294365847
1971-01-01	3.13050084952250
1972-01-01	3.05841808746222
1973-01-01	2.97640114923384
1974-01-01	2.88746946030311
1975-01-01	2.79291388162356
1976-01-01	2.72248806616503
1977-01-01	2.64797752279898
1978-01-01	2.57615205075546
1979-01-01	2.51170441604454
1980-01-01	2.45865287996500
1981-01-01	2.43490688050909
1982-01-01	2.41484019262210
1983-01-01	2.40198143037648
1984-01-01	2.40173648388072
1985-01-01	2.41566409948920
1986-01-01	2.45392522069432
1987-01-01	2.50428295502541
1988-01-01	2.55688583196730
1989-01-01	2.59901285733907
1990-01-01	2.62607481464709
1991-01-01	2.65710286568163
1992-01-01	2.67200977035141
1993-01-01	2.68081806765670
1994-01-01	2.69609858138536
1995-01-01	2.72297261986854
1996-01-01	2.76330062466491
1997-01-01	2.80837915652755
1998-01-01	2.85686905742307
1999-01-01	2.90629474627940
2000-01-01	2.95595773979657
2001-01-01	3.02284700003134
2002-01-01	3.08772197917585
2003-01-01	3.14946359858098
2004-01-01	3.20636517194820
2005-01-01	3.25640191135931
2006-01-01	3.31842368108487
2007-01-01	3.37633343675924
2008-01-01	3.42867242342209
2009-01-01	3.47288373751567
2010-01-01	3.50862042438554
2011-01-01	3.54587905753267
2012-01-01	3.57394648485269
2013-01-01	3.60421647661953
2014-01-01	3.65221737981613
2015-01-01	3.72596920962685
2016-01-01	3.82355816661186
2017-01-01	3.94128974573465