Year	Percent of Total
1960-01-01	3.23554414052134
1961-01-01	3.24507597999816
1962-01-01	3.25367916528271
1963-01-01	3.25676780918723
1964-01-01	3.25015515044659
1965-01-01	3.23118827285476
1966-01-01	3.24166693238839
1967-01-01	3.24137492790822
1968-01-01	3.23376916008618
1969-01-01	3.22196975412860
1970-01-01	3.20809494309002
1971-01-01	3.21450971632790
1972-01-01	3.21857609330377
1973-01-01	3.22099000536882
1974-01-01	3.22245227104386
1975-01-01	3.22339317931500
1976-01-01	3.24521293643680
1977-01-01	3.26532620901416
1978-01-01	3.27913793223107
1979-01-01	3.28116041175720
1980-01-01	3.26978380691442
1981-01-01	3.26079677548117
1982-01-01	3.24234521207050
1983-01-01	3.22199839309373
1984-01-01	3.20937729473750
1985-01-01	3.20943550962127
1986-01-01	3.23376169289173
1987-01-01	3.26709386842761
1988-01-01	3.30442837924617
1989-01-01	3.33939395575988
1990-01-01	3.36895963294458
1991-01-01	3.40154248540819
1992-01-01	3.42785102278349
1993-01-01	3.45181943041099
1994-01-01	3.47869701267418
1995-01-01	3.51088123052325
1996-01-01	3.54700674812866
1997-01-01	3.58721567282292
1998-01-01	3.62916757778472
1999-01-01	3.66996837140002
2000-01-01	3.70817758824993
2001-01-01	3.74069502728273
2002-01-01	3.77096138118362
2003-01-01	3.80002561907674
2004-01-01	3.82899974500819
2005-01-01	3.85926224294528
2006-01-01	3.88735204018985
2007-01-01	3.91791770909391
2008-01-01	3.95276919180282
2009-01-01	3.99420237980710
2010-01-01	4.04427063185848
2011-01-01	4.09749030125964
2012-01-01	4.15707401883408
2013-01-01	4.22707424589546
2014-01-01	4.31212039754730
2015-01-01	4.41446879524205
2016-01-01	4.52713728840770
2017-01-01	4.65194693141453