Annual Percent of Total
1960-01-01 51.0343656779764
1961-01-01 50.5502046998130
1962-01-01 50.2471017504965
1963-01-01 50.1183418614611
1964-01-01 50.1155751238305
1965-01-01 50.1969732848255
1966-01-01 50.2539033692240
1967-01-01 50.4304560563206
1968-01-01 50.7430954887827
1969-01-01 51.1611723068358
1970-01-01 51.6979952323264
1971-01-01 52.3075444497837
1972-01-01 52.9532030895048
1973-01-01 53.6471158868741
1974-01-01 54.3416697315189
1975-01-01 55.0218419764723
1976-01-01 55.6603605052075
1977-01-01 56.1520859003697
1978-01-01 56.5381013492421
1979-01-01 56.8847639558336
1980-01-01 57.2254335260116
1981-01-01 57.0418904761113
1982-01-01 57.0682862770847
1983-01-01 57.2108535163839
1984-01-01 57.2851111288138
1985-01-01 57.1582582066466
1986-01-01 57.2453371592539
1987-01-01 57.0642720149864
1988-01-01 56.7252308315725
1989-01-01 56.4338131526955
1990-01-01 56.2876318842181
1991-01-01 55.8358208955224
1992-01-01 55.5551097379930
1993-01-01 55.4378689628759
1994-01-01 55.4081725815497
1995-01-01 55.4136112183198
1996-01-01 55.5311949510183
1997-01-01 55.6544946622768
1998-01-01 55.8503985285101
1999-01-01 56.2049514258853
2000-01-01 56.7151624292112
2001-01-01 57.0150713969578
2002-01-01 57.6497257937098
2003-01-01 58.4577310309916
2004-01-01 59.1427182964812
2005-01-01 59.5353371242892
2006-01-01 60.2408232548271
2007-01-01 60.3337105834225
2008-01-01 60.1605038602194
2009-01-01 60.1284702887598
2010-01-01 60.3953162140046
2011-01-01 60.2851245986852
2012-01-01 60.5714124919100
2013-01-01 61.0356106325149
2014-01-01 61.3409621756686
2015-01-01 61.3520510288505
2016-01-01 61.3829275755059
2017-01-01 61.1135930170621