Year	Percent of Total
1960-01-01	42.3639924167802
1961-01-01	42.6559937359494
1962-01-01	42.9497065832001
1963-01-01	43.2147417938727
1964-01-01	43.4013174972487
1965-01-01	43.4955949944257
1966-01-01	43.7488179721250
1967-01-01	43.8876209977746
1968-01-01	43.9486653365505
1969-01-01	43.9766192735653
1970-01-01	43.9922696218475
1971-01-01	44.1824487667365
1972-01-01	44.3093818705996
1973-01-01	44.3918053138264
1974-01-01	44.4453521470192
1975-01-01	44.4802085537765
1976-01-01	44.6243827980664
1977-01-01	44.7297059787978
1978-01-01	44.7974664706734
1979-01-01	44.8178800393625
1980-01-01	44.7822682452626
1981-01-01	44.8835323757947
1982-01-01	44.9231563258789
1983-01-01	44.9091477454686
1984-01-01	44.8525863514996
1985-01-01	44.7614390795520
1986-01-01	44.8102386462234
1987-01-01	44.7901177016523
1988-01-01	44.7183464031119
1989-01-01	44.6172238108188
1990-01-01	44.5362087857424
1991-01-01	44.3939665514688
1992-01-01	44.2324774941732
1993-01-01	44.0521161389914
1994-01-01	43.8444247554112
1995-01-01	43.6023985838831
1996-01-01	43.4960893112257
1997-01-01	43.3504438297539
1998-01-01	43.1729971780497
1999-01-01	42.9812155761108
2000-01-01	42.7894323044383
2001-01-01	42.7032183017662
2002-01-01	42.5934050027540
2003-01-01	42.4696833505971
2004-01-01	42.3381758275340
2005-01-01	42.2001900692639
2006-01-01	42.1419989281271
2007-01-01	42.0698478548576
2008-01-01	41.9818877434446
2009-01-01	41.8744074005127
2010-01-01	41.7458986606956
2011-01-01	41.6738794811588
2012-01-01	41.5678099394262
2013-01-01	41.4300077700697
2014-01-01	41.2646592557942
2015-01-01	41.0746061121447
2016-01-01	40.8648920906704
2017-01-01	40.6309447478893