Year	Percent of Total
1960-01-01	7.32805062023772
1961-01-01	7.45438499225453
1962-01-01	7.59359627208664
1963-01-01	7.74395117375705
1964-01-01	7.89681596944688
1965-01-01	8.05030339723477
1966-01-01	8.26689572298447
1967-01-01	8.48215686684729
1968-01-01	8.70084701342440
1969-01-01	8.93223326153061
1970-01-01	9.18133990234080
1971-01-01	9.48615149328852
1972-01-01	9.79578910433758
1973-01-01	10.10134626440710
1974-01-01	10.38986936819120
1975-01-01	10.65384066836360
1976-01-01	10.99803419076020
1977-01-01	11.30974701133280
1978-01-01	11.58673395187980
1979-01-01	11.82417117186030
1980-01-01	12.01939834715990
1981-01-01	12.15055554134850
1982-01-01	12.24694422038840
1983-01-01	12.32589592565310
1984-01-01	12.41173649872220
1985-01-01	12.52228570497760
1986-01-01	12.69295572050700
1987-01-01	12.87604068678200
1988-01-01	13.06639049063240
1989-01-01	13.25518900005320
1990-01-01	13.43541179715390
1991-01-01	13.64124224839990
1992-01-01	13.82882798059440
1993-01-01	13.99817697463360
1994-01-01	14.14854376912980
1995-01-01	14.28119331784200
1996-01-01	14.43550771766830
1997-01-01	14.58107600801750
1998-01-01	14.72096001697830
1999-01-01	14.85716758701730
2000-01-01	14.99392631468980
2001-01-01	15.20719533719870
2002-01-01	15.41616147549770
2003-01-01	15.62226724822530
2004-01-01	15.82540486457460
2005-01-01	16.02705266682730
2006-01-01	16.19915984060850
2007-01-01	16.35695941913330
2008-01-01	16.54453409104150
2009-01-01	16.82359265427650
2010-01-01	17.22956691121630
2011-01-01	17.73845004547950
2012-01-01	18.35785463829540
2013-01-01	19.03421172288050
2014-01-01	19.68583719632350
2015-01-01	20.26446351546140
2016-01-01	20.78534550870300
2017-01-01	21.22848021384580