Year	Percent of Total
1960-01-01	2.83743486380713
1961-01-01	2.87523119486314
1962-01-01	2.89795274084400
1963-01-01	2.90554508104106
1964-01-01	2.89864832679316
1965-01-01	2.87818593341511
1966-01-01	2.92006214947394
1967-01-01	2.94850773184875
1968-01-01	2.96291104257620
1969-01-01	2.96294418241374
1970-01-01	2.94886190370243
1971-01-01	2.99401372069639
1972-01-01	3.02408357239003
1973-01-01	3.03980216074160
1974-01-01	3.04297092231239
1975-01-01	3.03546305859027
1976-01-01	3.07088968956786
1977-01-01	3.09483858619370
1978-01-01	3.10703734782721
1979-01-01	3.10737789998658
1980-01-01	3.09644412129049
1981-01-01	3.11754323382416
1982-01-01	3.12339113955612
1983-01-01	3.11581486226121
1984-01-01	3.09652714837029
1985-01-01	3.06731060257136
1986-01-01	3.05770979629581
1987-01-01	3.03348379594058
1988-01-01	2.99613482739158
1989-01-01	2.94862792236581
1990-01-01	2.89566040527372
1991-01-01	2.89396088156544
1992-01-01	2.86505398339356
1993-01-01	2.80865108273189
1994-01-01	2.72278990134748
1995-01-01	2.60411025589621
1996-01-01	2.59780260838091
1997-01-01	2.57180716091563
1998-01-01	2.52484928724108
1999-01-01	2.45540417183908
2000-01-01	2.36310213818251
2001-01-01	2.36850639999139
2002-01-01	2.36836563103161
2003-01-01	2.36380116813978
2004-01-01	2.35779763387469
2005-01-01	2.35397805625957
2006-01-01	2.38478962475712
2007-01-01	2.40615072903508
2008-01-01	2.41975666675101
2009-01-01	2.42682551907528
2010-01-01	2.42778754923576
2011-01-01	2.46008132260245
2012-01-01	2.48473899968712
2013-01-01	2.50066490139740
2014-01-01	2.50628534846356
2015-01-01	2.50187058908875
2016-01-01	2.52535427023914
2017-01-01	2.53753632953528