Year	Percent of Total
1960-01-01	3.62181787571341
1961-01-01	3.62091446566730
1962-01-01	3.61391049549104
1963-01-01	3.60160020935829
1964-01-01	3.58461659501724
1965-01-01	3.56428591336878
1966-01-01	3.54771211699464
1967-01-01	3.52678404711131
1968-01-01	3.50196733689888
1969-01-01	3.47317714676761
1970-01-01	3.44012367921330
1971-01-01	3.40157685780383
1972-01-01	3.36202007727998
1973-01-01	3.32387313554545
1974-01-01	3.28853968377187
1975-01-01	3.25607309916684
1976-01-01	3.20225595000034
1977-01-01	3.15142710946737
1978-01-01	3.10390514110859
1979-01-01	3.05888445721234
1980-01-01	3.01671385917848
1981-01-01	2.92981510632980
1982-01-01	2.84443993888531
1983-01-01	2.76357110354385
1984-01-01	2.68904194941004
1985-01-01	2.62023646014156
1986-01-01	2.62139797701523
1987-01-01	2.64393493996142
1988-01-01	2.68620263786287
1989-01-01	2.74401203761577
1990-01-01	2.81454159920352
1991-01-01	2.84167571298002
1992-01-01	2.86211968318011
1993-01-01	2.87954758605244
1994-01-01	2.89592263486226
1995-01-01	2.91115835152529
1996-01-01	2.92969560587214
1997-01-01	2.94722391176759
1998-01-01	2.96495030946375
1999-01-01	2.98285645808012
2000-01-01	3.00042207032913
2001-01-01	2.99150490677816
2002-01-01	2.98040180937838
2003-01-01	2.96995645364902
2004-01-01	2.96389539061057
2005-01-01	2.96546164350911
2006-01-01	2.96202329038122
2007-01-01	2.96660906064646
2008-01-01	2.97503119606704
2009-01-01	2.98036208926342
2010-01-01	2.98090373415044
2011-01-01	2.97081027635790
2012-01-01	2.96019883136276
2013-01-01	2.96128073839061
2014-01-01	2.98948016621133
2015-01-01	3.05330228869888
2016-01-01	3.16300935747704
2017-01-01	3.29541860695357