Year	Percent of Total
1960-01-01	42.1447350553728
1961-01-01	42.2711986077777
1962-01-01	42.3686317095594
1963-01-01	42.4265697875689
1964-01-01	42.4248765758097
1965-01-01	42.3598817087595
1966-01-01	42.4299236305734
1967-01-01	42.4172981112731
1968-01-01	42.3541526846294
1969-01-01	42.2832630014723
1970-01-01	42.2268701263341
1971-01-01	42.3261345309013
1972-01-01	42.4142357844033
1973-01-01	42.4890050207465
1974-01-01	42.5292840270615
1975-01-01	42.5167052969661
1976-01-01	43.0009554778309
1977-01-01	43.4192156365021
1978-01-01	43.7812791608799
1979-01-01	44.1156002753694
1980-01-01	44.4410682891855
1981-01-01	44.4949218821698
1982-01-01	44.5255880057932
1983-01-01	44.5340757260005
1984-01-01	44.5175233752354
1985-01-01	44.4804601428781
1986-01-01	44.4722424073739
1987-01-01	44.4397071261814
1988-01-01	44.3897773670838
1989-01-01	44.3303801848440
1990-01-01	44.2651495653840
1991-01-01	44.4148076984105
1992-01-01	44.5219987815287
1993-01-01	44.5816390095344
1994-01-01	44.5723760542404
1995-01-01	44.4723669357490
1996-01-01	44.4852718682800
1997-01-01	44.3520928132575
1998-01-01	44.1007089629245
1999-01-01	43.7688360333079
2000-01-01	43.3723428049892
2001-01-01	42.8232132277220
2002-01-01	42.2690486719506
2003-01-01	41.6751319436180
2004-01-01	41.0075371539587
2005-01-01	40.2696824797107
2006-01-01	39.4410085486334
2007-01-01	38.6110292687789
2008-01-01	37.7965992475451
2009-01-01	37.0199231603976
2010-01-01	36.2883536649209
2011-01-01	35.7101704006024
2012-01-01	35.1367672465059
2013-01-01	34.5940762395341
2014-01-01	34.1160668980294
2015-01-01	33.7120817074874
2016-01-01	33.2684901188204
2017-01-01	32.8848554131137