Year	Percent of Total
1960-01-01	56.4566878554931
1961-01-01	56.1389742366533
1962-01-01	55.8116761251618
1963-01-01	55.5170563870645
1964-01-01	55.3202478044250
1965-01-01	55.2460908624386
1966-01-01	55.0668556216044
1967-01-01	55.0252272643703
1968-01-01	55.0832705138733
1969-01-01	55.1887714065416
1970-01-01	55.3147228523301
1971-01-01	55.3126278870763
1972-01-01	55.3543505968710
1973-01-01	55.4350169668358
1974-01-01	55.5555917561814
1975-01-01	55.7125638349871
1976-01-01	55.7356210898031
1977-01-01	55.8221249848476
1978-01-01	55.9523987066491
1979-01-01	56.1050947691600
1980-01-01	56.2674416639314
1981-01-01	56.2961402556067
1982-01-01	56.3521955369987
1983-01-01	56.4349041257224
1984-01-01	56.5500643246662
1985-01-01	56.6993646524420
1986-01-01	56.7136920159089
1987-01-01	56.7981592460561
1988-01-01	56.9352520931104
1989-01-01	57.1067597791732
1990-01-01	57.3047613299491
1991-01-01	57.4294371613436
1992-01-01	57.5944673240249
1993-01-01	57.8002720907484
1994-01-01	58.0507951399301
1995-01-01	58.3454610172583
1996-01-01	58.5901568681329
1997-01-01	58.8730899952222
1998-01-01	59.1912017464026
1999-01-01	59.5389486317024
2000-01-01	59.9090620584820
2001-01-01	60.1992194241296
2002-01-01	60.5261869772808
2003-01-01	60.8772640680426
2004-01-01	61.2373785760791
2005-01-01	61.5983839865304
2006-01-01	61.8895076466745
2007-01-01	62.1811715550387
2008-01-01	62.4784195618275
2009-01-01	62.7943769607530
2010-01-01	63.1351382089909
2011-01-01	63.4406849853606
2012-01-01	63.7866007985402
2013-01-01	64.1515469409880
2014-01-01	64.5036172908718
2015-01-01	64.8250013909544
2016-01-01	65.1156984069694
2017-01-01	65.3615778879828