Year	Percent of Total
1960-01-01	57.1549906881747
1961-01-01	56.8833994227412
1962-01-01	56.5116594396643
1963-01-01	56.1302040594689
1964-01-01	55.8870609851776
1965-01-01	55.8415807473233
1966-01-01	55.6664047977459
1967-01-01	55.6827859684332
1968-01-01	55.8259200587051
1969-01-01	55.9973652959965
1970-01-01	56.1464316049878
1971-01-01	56.0599400446006
1972-01-01	56.0137267070360
1973-01-01	55.9881635323958
1974-01-01	55.9771461068231
1975-01-01	55.9789518298845
1976-01-01	55.7792646854772
1977-01-01	55.6132515118919
1978-01-01	55.4783331389470
1979-01-01	55.3792759110494
1980-01-01	55.3185064476882
1981-01-01	55.0718833550506
1982-01-01	54.8971195155888
1983-01-01	54.7762297473085
1984-01-01	54.6906933903591
1985-01-01	54.6325582296438
1986-01-01	54.4155604633517
1987-01-01	54.2503738790422
1988-01-01	54.1333404051894
1989-01-01	54.0638009733942
1990-01-01	54.0409333501019
1991-01-01	54.0741688747665
1992-01-01	54.1798145543501
1993-01-01	54.3441114994581
1994-01-01	54.5540522343035
1995-01-01	54.7989043382284
1996-01-01	54.8325032407100
1997-01-01	54.8879907518615
1998-01-01	54.9662817327648
1999-01-01	55.0796760695982
2000-01-01	55.2422735589211
2001-01-01	55.3760677453484
2002-01-01	55.5213104173181
2003-01-01	55.6798882336525
2004-01-01	55.8501688440550
2005-01-01	56.0408898699145
2006-01-01	56.4597188856488
2007-01-01	56.8511118909067
2008-01-01	57.2281261960188
2009-01-01	57.6278884233010
2010-01-01	58.0798705938544
2011-01-01	58.8288232210995
2012-01-01	59.6482449771564
2013-01-01	60.4891173261972
2014-01-01	61.2764266631774
2015-01-01	61.9689148787690
2016-01-01	62.6801729896703
2017-01-01	63.2976941339494