Year	Percent of Total
1960-01-01	57.9298822512234
1961-01-01	57.9160280818911
1962-01-01	57.8943400020107
1963-01-01	57.8920635099800
1964-01-01	57.9246243862693
1965-01-01	57.9911572035224
1966-01-01	57.9838381432771
1967-01-01	58.0779559502396
1968-01-01	58.2056862599063
1969-01-01	58.2661448368666
1970-01-01	58.2149886203313
1971-01-01	58.4126801310976
1972-01-01	58.4139361370382
1973-01-01	58.3238695870321
1974-01-01	58.2887893522400
1975-01-01	58.3728784602117
1976-01-01	58.2434054424366
1977-01-01	58.3372174636983
1978-01-01	58.5662251764580
1979-01-01	58.7975810684106
1980-01-01	58.9775755301455
1981-01-01	59.0790719424295
1982-01-01	59.0914199968049
1983-01-01	59.0840415700203
1984-01-01	59.1694742787445
1985-01-01	59.4046102633999
1986-01-01	59.5972498884174
1987-01-01	59.9255269111026
1988-01-01	60.3770909963038
1989-01-01	60.8893756575372
1990-01-01	61.4162275229831
1991-01-01	62.1590577050785
1992-01-01	62.8600783482333
1993-01-01	63.5397908568877
1994-01-01	64.2220867492243
1995-01-01	64.9034312873044
1996-01-01	65.6610909849834
1997-01-01	66.3724146550647
1998-01-01	67.0239456935879
1999-01-01	67.5863918608931
2000-01-01	68.0418657775875
2001-01-01	68.4487962401386
2002-01-01	68.7817884418835
2003-01-01	69.0252514663986
2004-01-01	69.1660355231088
2005-01-01	69.2001404232684
2006-01-01	69.1090238580461
2007-01-01	68.9418297513479
2008-01-01	68.6983819677035
2009-01-01	68.4082140705559
2010-01-01	68.1050148176068
2011-01-01	67.4637577186360
2012-01-01	66.8257121401624
2013-01-01	66.2069595962552
2014-01-01	65.6096528916873
2015-01-01	65.0349236730142
2016-01-01	64.7179754544889
2017-01-01	64.4347755413714