Year	Percent of Total
1960-01-01	43.9068352403010
1961-01-01	44.2184048580809
1962-01-01	44.5194860258593
1963-01-01	44.7747896528896
1964-01-01	44.9146889991710
1965-01-01	44.9096032557164
1966-01-01	45.0867212198001
1967-01-01	45.0797681700292
1968-01-01	44.9444243596487
1969-01-01	44.7549435691258
1970-01-01	44.5529247763655
1971-01-01	44.7173471866428
1972-01-01	44.7999100133168
1973-01-01	44.8240990780466
1974-01-01	44.7973366361621
1975-01-01	44.7255981260113
1976-01-01	45.2185273918914
1977-01-01	45.6002932052346
1978-01-01	45.9054628508644
1979-01-01	46.1705435462940
1980-01-01	46.4112336092790
1981-01-01	46.7251316357404
1982-01-01	46.9808493462650
1983-01-01	47.1748604006724
1984-01-01	47.2885254654433
1985-01-01	47.3150187409268
1986-01-01	47.4301762790864
1987-01-01	47.4112171114853
1988-01-01	47.3006099063925
1989-01-01	47.1463035231832
1990-01-01	46.9689636200459
1991-01-01	46.8513937655503
1992-01-01	46.7137043921180
1993-01-01	46.5402064996246
1994-01-01	46.3008681801932
1995-01-01	45.9827389046677
1996-01-01	45.8656305266826
1997-01-01	45.6613191413107
1998-01-01	45.3925844886702
1999-01-01	45.0983246141363
2000-01-01	44.8032143092732
2001-01-01	44.5769434832335
2002-01-01	44.3400464813370
2003-01-01	44.1021123625830
2004-01-01	43.8710073728015
2005-01-01	43.6549984686168
2006-01-01	43.5475573912868
2007-01-01	43.4506188836252
2008-01-01	43.3665982271160
2009-01-01	43.2969877818489
2010-01-01	43.2428845911605
2011-01-01	43.2294256558386
2012-01-01	43.2070374946921
2013-01-01	43.1767693650002
2014-01-01	43.1313359288954
2015-01-01	43.0603230528102
2016-01-01	42.9953345574318
2017-01-01	42.8816205754659