Year	Percent of Total
1960-01-01	41.4481488655403
1961-01-01	41.7092436064720
1962-01-01	42.0090902877452
1963-01-01	42.3141642089081
1964-01-01	42.5599341361578
1965-01-01	42.7203481003566
1966-01-01	43.0324271484409
1967-01-01	43.2406782344108
1968-01-01	43.3711031117178
1969-01-01	43.4622569147430
1970-01-01	43.5369837115936
1971-01-01	43.7758819638041
1972-01-01	43.9609134564852
1973-01-01	44.1031272858968
1974-01-01	44.2102736498640
1975-01-01	44.2886303063422
1976-01-01	44.5162351252766
1977-01-01	44.6678240895466
1978-01-01	44.7651271188354
1979-01-01	44.8413443459098
1980-01-01	44.9181121360113
1981-01-01	45.1249478915490
1982-01-01	45.3162388955878
1983-01-01	45.4703028325973
1984-01-01	45.5163728776350
1985-01-01	45.3760110920821
1986-01-01	45.4896897266959
1987-01-01	45.5113889721833
1988-01-01	45.4291507512390
1989-01-01	45.2667456398588
1990-01-01	45.0612998466550
1991-01-01	44.9152464219443
1992-01-01	44.6388023309104
1993-01-01	44.3001067867584
1994-01-01	44.0399724773149
1995-01-01	44.0312961482183
1996-01-01	43.8624137964082
1997-01-01	43.7168349467388
1998-01-01	43.6228519730214
1999-01-01	43.4970989402886
2000-01-01	43.2325355812852
2001-01-01	43.3343964759830
2002-01-01	43.3702062416765
2003-01-01	43.3362973821277
2004-01-01	43.2969379935991
2005-01-01	43.3241139079427
2006-01-01	43.3873011678878
2007-01-01	43.4335193507873
2008-01-01	43.4683058362383
2009-01-01	43.4538851610168
2010-01-01	43.3476903593478
2011-01-01	43.2518125177665
2012-01-01	43.1120133787294
2013-01-01	42.9157049766336
2014-01-01	42.6683037494617
2015-01-01	42.3851253249996
2016-01-01	42.1114550774921
2017-01-01	41.8109320007625