Year	Percent of Total
1960-01-01	53.8569966026153
1961-01-01	53.6054690616574
1962-01-01	53.4287253604059
1963-01-01	53.3110566677283
1964-01-01	53.2430038896802
1965-01-01	53.2181235847421
1966-01-01	52.9622277586950
1967-01-01	52.7935367274181
1968-01-01	52.6913424857016
1969-01-01	52.6361916852898
1970-01-01	52.6165507882866
1971-01-01	52.3897034838159
1972-01-01	52.2335906415660
1973-01-01	52.1335649472948
1974-01-01	52.0788562586420
1975-01-01	52.0625813637223
1976-01-01	51.8802495487391
1977-01-01	51.7539888019643
1978-01-01	51.6694495815516
1979-01-01	51.6184529154808
1980-01-01	51.5990901416912
1981-01-01	51.3922492216126
1982-01-01	51.2594658324875
1983-01-01	51.1871815802757
1984-01-01	51.1620049215359
1985-01-01	51.1736145454645
1986-01-01	51.0326091400787
1987-01-01	50.9616332755190
1988-01-01	50.9455080883248
1989-01-01	50.9722427763299
1990-01-01	51.0337140932904
1991-01-01	51.0077367383003
1992-01-01	51.0386741267217
1993-01-01	51.1137049613020
1994-01-01	51.2242809159385
1995-01-01	51.3673874684125
1996-01-01	51.3360797466546
1997-01-01	51.3534186632532
1998-01-01	51.4084833052664
1999-01-01	51.4914662321371
2000-01-01	51.5957190200348
2001-01-01	51.5978123890090
2002-01-01	51.6467362630668
2003-01-01	51.7273681833668
2004-01-01	51.8273698357545
2005-01-01	51.9427177820354
2006-01-01	51.9662301138830
2007-01-01	52.0214962097059
2008-01-01	52.1090225006987
2009-01-01	52.2307624897067
2010-01-01	52.3851614993003
2011-01-01	52.5194487373401
2012-01-01	52.6960112866023
2013-01-01	52.9059117368150
2014-01-01	53.1398433210109
2015-01-01	53.3919712131354
2016-01-01	53.6042892474284
2017-01-01	53.8422776327678