Year	Percent of Total
1960-01-01	49.8900944980641
1961-01-01	49.8009377419163
1962-01-01	49.6091499692446
1963-01-01	49.4186344855532
1964-01-01	49.3730908875370
1965-01-01	49.5252221708574
1966-01-01	49.6190185612876
1967-01-01	49.8879856545602
1968-01-01	50.2685530881667
1969-01-01	50.6607212894438
1970-01-01	51.0136105205544
1971-01-01	51.3011391397071
1972-01-01	51.5741903842807
1973-01-01	51.8386626666751
1974-01-01	52.1128924633326
1975-01-01	52.4045647616895
1976-01-01	52.6407300897080
1977-01-01	52.8819722864428
1978-01-01	53.1324855086581
1979-01-01	53.3969438128273
1980-01-01	53.6758553838296
1981-01-01	53.9052322303709
1982-01-01	54.1687324202069
1983-01-01	54.4479973416789
1984-01-01	54.7192102488835
1985-01-01	54.9711278594545
1986-01-01	55.1576666304925
1987-01-01	55.3232982823135
1988-01-01	55.4874199180715
1989-01-01	55.6809031918155
1990-01-01	55.9188409486069
1991-01-01	56.0989426621106
1992-01-01	56.3391996795844
1993-01-01	56.6152125437735
1994-01-01	56.8917978030146
1995-01-01	57.1532030566308
1996-01-01	57.3821691922277
1997-01-01	57.5870073295522
1998-01-01	57.7886781474661
1999-01-01	58.0114009922368
2000-01-01	58.2605845511327
2001-01-01	58.4613266137214
2002-01-01	58.6804980722062
2003-01-01	58.9115378399983
2004-01-01	59.1594881122884
2005-01-01	59.4489685257952
2006-01-01	59.8436040215686
2007-01-01	60.2896650136533
2008-01-01	60.8161051105242
2009-01-01	61.3956867619967
2010-01-01	61.9610666868786
2011-01-01	62.2464087699629
2012-01-01	62.5290737341757
2013-01-01	62.7829285948181
2014-01-01	63.0027892779911
2015-01-01	63.1989068739671
2016-01-01	63.3477481300805
2017-01-01	63.4816055076870