Year	Percent of Total
1960-01-01	2.82751079966854
1961-01-01	2.83996413899364
1962-01-01	2.84311988705910
1963-01-01	2.83858923637676
1964-01-01	2.82864427798224
1965-01-01	2.81484476829411
1966-01-01	2.84262205468662
1967-01-01	2.86384968787203
1968-01-01	2.87823901122211
1969-01-01	2.88571904579323
1970-01-01	2.88730091153348
1971-01-01	2.92264441249839
1972-01-01	2.95077193489326
1973-01-01	2.97211531499637
1974-01-01	2.98676727877743
1975-01-01	2.99513045849410
1976-01-01	3.02378888081591
1977-01-01	3.04345185000885
1978-01-01	3.05528529610953
1979-01-01	3.06058839717692
1980-01-01	3.06034447455708
1981-01-01	3.07396028761261
1982-01-01	3.07930477631101
1983-01-01	3.07730843733952
1984-01-01	3.06897982223636
1985-01-01	3.05529856695446
1986-01-01	3.07714810910262
1987-01-01	3.09427573824342
1988-01-01	3.10649706340498
1989-01-01	3.11360931908862
1990-01-01	3.11598282468872
1991-01-01	3.13969423687564
1992-01-01	3.15773538655361
1993-01-01	3.17151744466346
1994-01-01	3.18284672574552
1995-01-01	3.19316616017800
1996-01-01	3.21914890509005
1997-01-01	3.24086777719169
1998-01-01	3.25840034980363
1999-01-01	3.27071559358973
2000-01-01	3.27736005214465
2001-01-01	3.29695807727560
2002-01-01	3.30976977487552
2003-01-01	3.31827280004111
2004-01-01	3.32526088957285
2005-01-01	3.33248427286039
2006-01-01	3.36045080142902
2007-01-01	3.38524471950188
2008-01-01	3.40652850604008
2009-01-01	3.42376679008784
2010-01-01	3.43743618019843
2011-01-01	3.46411546952020
2012-01-01	3.48702397117182
2013-01-01	3.50743373046557
2014-01-01	3.52631057967753
2015-01-01	3.54464010863614
2016-01-01	3.57465645491053
2017-01-01	3.60193296237237