Year	Percent of Total
1960-01-01	4.08030502900305
1961-01-01	4.06811057281277
1962-01-01	4.03541929161417
1963-01-01	4.00041170617902
1964-01-01	3.97150729117667
1965-01-01	3.94202135535776
1966-01-01	3.96074703105110
1967-01-01	3.98358585858586
1968-01-01	3.99505065346841
1969-01-01	4.00394477317554
1970-01-01	4.00309994336642
1971-01-01	4.07403062122368
1972-01-01	4.13582745460853
1973-01-01	4.19318927868010
1974-01-01	4.26930782471289
1975-01-01	4.37514837520423
1976-01-01	4.54174448364114
1977-01-01	4.72178387650086
1978-01-01	4.91653483170585
1979-01-01	5.07969753019258
1980-01-01	5.19866016720678
1981-01-01	5.41838885391290
1982-01-01	5.59573763250883
1983-01-01	5.74128617094041
1984-01-01	5.86779780841287
1985-01-01	5.97575305952825
1986-01-01	6.22883634408290
1987-01-01	6.48979291031027
1988-01-01	6.77174982850666
1989-01-01	7.09021868011467
1990-01-01	7.46821398584623
1991-01-01	7.55047766205595
1992-01-01	7.66218013357300
1993-01-01	7.75687037089994
1994-01-01	7.80685731814443
1995-01-01	7.79146687675736
1996-01-01	7.59507060876924
1997-01-01	7.34894969063147
1998-01-01	7.08068778099210
1999-01-01	6.82015373147096
2000-01-01	6.57901033690658
2001-01-01	6.52150910565856
2002-01-01	6.49618621473118
2003-01-01	6.52400536125462
2004-01-01	6.60004305607487
2005-01-01	6.72358352100210
2006-01-01	6.72971506406352
2007-01-01	6.74319606920476
2008-01-01	6.74430675403880
2009-01-01	6.72251845994379
2010-01-01	6.66694837367025
2011-01-01	6.63922523219006
2012-01-01	6.58627566467239
2013-01-01	6.53213935230618
2014-01-01	6.52642225031606
2015-01-01	6.58306896310159
2016-01-01	6.72820736309341
2017-01-01	6.93251774301063