Year	Percent of Total
1960-01-01	4.01373028401139
1961-01-01	3.93427737865016
1962-01-01	3.83663274606874
1963-01-01	3.72948854987105
1964-01-01	3.62319779612421
1965-01-01	3.52176698043668
1966-01-01	3.48607996922963
1967-01-01	3.44883310239611
1968-01-01	3.40789754189916
1969-01-01	3.36041359335483
1970-01-01	3.30572935900633
1971-01-01	3.30255506694587
1972-01-01	3.29146502438727
1973-01-01	3.26950601746924
1974-01-01	3.23282628871655
1975-01-01	3.18061527464521
1976-01-01	3.15757106397791
1977-01-01	3.12219886958395
1978-01-01	3.07826067424776
1979-01-01	3.02852207140435
1980-01-01	2.97517961778432
1981-01-01	2.95446805180882
1982-01-01	2.92936101645399
1983-01-01	2.91095273667885
1984-01-01	2.91298407017809
1985-01-01	2.94240282272017
1986-01-01	3.00887945678694
1987-01-01	3.09079458243669
1988-01-01	3.17911512589453
1989-01-01	3.26340303360999
1990-01-01	3.34049873737654
1991-01-01	3.42866575440870
1992-01-01	3.51255248431628
1993-01-01	3.59623020497729
1994-01-01	3.68292071385368
1995-01-01	3.77263838911890
1996-01-01	3.86385294833132
1997-01-01	3.95192790266557
1998-01-01	4.03724345127740
1999-01-01	4.12078756079140
2000-01-01	4.20455020057354
2001-01-01	4.34595506102606
2002-01-01	4.49286170595056
2003-01-01	4.64309843444190
2004-01-01	4.78895845991861
2005-01-01	4.92304294758906
2006-01-01	4.94274292594417
2007-01-01	4.94848593391663
2008-01-01	4.94389073253103
2009-01-01	4.93579208377967
2010-01-01	4.93100943117171
2011-01-01	4.91835500281343
2012-01-01	4.90820612258101
2013-01-01	4.91308211243583
2014-01-01	4.95135943266802
2015-01-01	5.03463014283166
2016-01-01	5.21490673567668
2017-01-01	5.43958273094315