Year	Percent of Total
1960-01-01	45.1386025756069
1961-01-01	45.6445086021251
1962-01-01	45.9701630409681
1963-01-01	46.1330387935893
1964-01-01	46.1750137589433
1965-01-01	46.1348029190795
1966-01-01	46.1155945131587
1967-01-01	45.9710551850858
1968-01-01	45.6912610350693
1969-01-01	45.2936732015747
1970-01-01	44.7731447106178
1971-01-01	44.1441614608361
1972-01-01	43.4669847039225
1973-01-01	42.7393478098649
1974-01-01	42.0117690327326
1975-01-01	41.3130562453552
1976-01-01	40.7149364917734
1977-01-01	40.2816405562401
1978-01-01	39.9673962054733
1979-01-01	39.7019109151198
1980-01-01	39.4310655723891
1981-01-01	39.5822593251626
1982-01-01	39.5026263952725
1983-01-01	39.2889522082632
1984-01-01	39.1508006054330
1985-01-01	39.2169117072637
1986-01-01	39.1220733233615
1987-01-01	39.3273962623214
1988-01-01	39.7232915569192
1989-01-01	40.0846740050805
1990-01-01	40.2889023918688
1991-01-01	40.6824966078697
1992-01-01	40.9207024301515
1993-01-01	41.0227287734915
1994-01-01	41.0728958797981
1995-01-01	41.1141129551010
1996-01-01	41.0001647509093
1997-01-01	40.8996807343111
1998-01-01	40.7394236664623
1999-01-01	40.4310199358774
2000-01-01	39.9651683529607
2001-01-01	39.5956113582893
2002-01-01	38.8789027168748
2003-01-01	38.0122616570111
2004-01-01	37.3009211194804
2005-01-01	36.9141619279718
2006-01-01	36.1860810524082
2007-01-01	36.0914121959070
2008-01-01	36.2789516456725
2009-01-01	36.3197040808209
2010-01-01	36.0548260141059
2011-01-01	36.1546399633084
2012-01-01	35.8521005881084
2013-01-01	35.3526512185009
2014-01-01	35.0051603324340
2015-01-01	34.9444429617373
2016-01-01	34.8197036583767
2017-01-01	34.9911510507053