Year	Percent of Total
1960-01-01	3.44313440258019
1961-01-01	3.41581967673294
1962-01-01	3.36836406673704
1963-01-01	3.30491624894486
1964-01-01	3.23134886935059
1965-01-01	3.15062176911377
1966-01-01	3.15776491952506
1967-01-01	3.15452818774565
1968-01-01	3.14056630506120
1969-01-01	3.11471917767590
1970-01-01	3.07822464257531
1971-01-01	3.11751848099366
1972-01-01	3.13743938878912
1973-01-01	3.13984034631714
1974-01-01	3.12699557823012
1975-01-01	3.09968074337715
1976-01-01	3.15523937483125
1977-01-01	3.19639675851953
1978-01-01	3.22071215213111
1979-01-01	3.22478089905539
1980-01-01	3.20587636876865
1981-01-01	3.25013116085637
1982-01-01	3.28345703805799
1983-01-01	3.30552192538981
1984-01-01	3.31683641018752
1985-01-01	3.31818547437867
1986-01-01	3.35582815164719
1987-01-01	3.38954894031998
1988-01-01	3.41929855575690
1989-01-01	3.44286919398363
1990-01-01	3.45819813431143
1991-01-01	3.46201145249955
1992-01-01	3.46849562010511
1993-01-01	3.47855354758659
1994-01-01	3.49543780853628
1995-01-01	3.52365524172827
1996-01-01	3.51657142800931
1997-01-01	3.49927344582410
1998-01-01	3.47518145020690
1999-01-01	3.44603605665924
2000-01-01	3.41208412829995
2001-01-01	3.39280218487307
2002-01-01	3.36259602762071
2003-01-01	3.32247100060065
2004-01-01	3.27306116638492
2005-01-01	3.21518800340298
2006-01-01	3.21335134962275
2007-01-01	3.20531594050230
2008-01-01	3.18903876358574
2009-01-01	3.16146678584731
2010-01-01	3.12243553696116
2011-01-01	3.11443321670622
2012-01-01	3.09521747566740
2013-01-01	3.07310246549789
2014-01-01	3.05810617737871
2015-01-01	3.05495589351656
2016-01-01	3.09187923385138
2017-01-01	3.13488623574919