Year	Percent of Total
1960-01-01	3.43083686787937
1961-01-01	3.38287525271843
1962-01-01	3.34081652491167
1963-01-01	3.29990225186214
1964-01-01	3.25362225891761
1965-01-01	3.20024126224746
1966-01-01	3.21611418693109
1967-01-01	3.22725909928677
1968-01-01	3.24035199359553
1969-01-01	3.26487459838286
1970-01-01	3.30502339045859
1971-01-01	3.37255108278196
1972-01-01	3.44042179919891
1973-01-01	3.50037584003310
1974-01-01	3.54364201258622
1975-01-01	3.56717511201970
1976-01-01	3.58249926436934
1977-01-01	3.58577342984420
1978-01-01	3.58370439109937
1979-01-01	3.58351260876416
1980-01-01	3.58916157086561
1981-01-01	3.62096217305417
1982-01-01	3.65030334194779
1983-01-01	3.67472214174912
1984-01-01	3.69116536249414
1985-01-01	3.69935345615106
1986-01-01	3.70687602223914
1987-01-01	3.70366717119186
1988-01-01	3.69364703914612
1989-01-01	3.68422712377889
1990-01-01	3.68169520877248
1991-01-01	3.70500393589579
1992-01-01	3.73333142583882
1993-01-01	3.76186325424403
1994-01-01	3.78457002873983
1995-01-01	3.80030891512943
1996-01-01	3.82152753125921
1997-01-01	3.83152584067247
1998-01-01	3.84119828535231
1999-01-01	3.86480378999453
2000-01-01	3.90974435520518
2001-01-01	4.02206734681899
2002-01-01	4.13443453895317
2003-01-01	4.23064751518134
2004-01-01	4.31283585846077
2005-01-01	4.40295684313343
2006-01-01	4.54514124048724
2007-01-01	4.67456713580358
2008-01-01	4.77722955151639
2009-01-01	4.85776632767602
2010-01-01	4.93623980601508
2011-01-01	5.09720089255407
2012-01-01	5.27556374161583
2013-01-01	5.46672867731898
2014-01-01	5.66347438536904
2015-01-01	5.86259777031363
2016-01-01	6.07629428229760
2017-01-01	6.29260178197349