Year	Percent of Total
1960-01-01	4.26373843264250
1961-01-01	4.15586337445007
1962-01-01	4.04394032877998
1963-01-01	3.93432967820513
1964-01-01	3.82628858632051
1965-01-01	3.71694170824272
1966-01-01	3.56286824363291
1967-01-01	3.44197493221243
1968-01-01	3.35017676594080
1969-01-01	3.28581413590363
1970-01-01	3.24862282151569
1971-01-01	3.20700983336147
1972-01-01	3.16231965103385
1973-01-01	3.11688885736519
1974-01-01	3.07372234994137
1975-01-01	3.03463346579942
1976-01-01	3.07447540622499
1977-01-01	3.11423693842524
1978-01-01	3.14880465981740
1979-01-01	3.17234541702995
1980-01-01	3.18376430137524
1981-01-01	3.26707413843612
1982-01-01	3.34056329642562
1983-01-01	3.40329975594852
1984-01-01	3.46374730796841
1985-01-01	3.52933457873573
1986-01-01	3.43911267558862
1987-01-01	3.36796021122044
1988-01-01	3.30826471282687
1989-01-01	3.25128872470084
1990-01-01	3.19602244801552
1991-01-01	3.11328322631575
1992-01-01	3.03777684480462
1993-01-01	2.97725395167029
1994-01-01	2.93881667979617
1995-01-01	2.92553703292262
1996-01-01	2.95084803513208
1997-01-01	2.97591172010984
1998-01-01	3.00173785570846
1999-01-01	3.03021057851813
2000-01-01	3.06321806420765
2001-01-01	3.12133555098487
2002-01-01	3.18446112785504
2003-01-01	3.25034919009023
2004-01-01	3.31471142668494
2005-01-01	3.37333313966075
2006-01-01	3.43311484957110
2007-01-01	3.49346564638488
2008-01-01	3.55300962029467
2009-01-01	3.61039161333717
2010-01-01	3.66515881203889
2011-01-01	3.67382302414685
2012-01-01	3.68577177837475
2013-01-01	3.70294565948104
2014-01-01	3.72767162362166
2015-01-01	3.76298324916025
2016-01-01	3.78569686632609
2017-01-01	3.81011698914686