Year	Percent of Total
1960-01-01	60.2876433508119
1961-01-01	60.2476108483248
1962-01-01	59.7210996131484
1963-01-01	58.9580373923291
1964-01-01	58.3112221088445
1965-01-01	57.9326183960554
1966-01-01	57.2022691768500
1967-01-01	56.9635117902169
1968-01-01	56.9706252948447
1969-01-01	56.8807569793184
1970-01-01	56.5610835326134
1971-01-01	56.5055923019278
1972-01-01	56.1558729349717
1973-01-01	55.7312120724686
1974-01-01	55.5731584768533
1975-01-01	55.8408580568700
1976-01-01	56.2642971893820
1977-01-01	57.1396662888648
1978-01-01	58.3160683864888
1979-01-01	59.5105903578599
1980-01-01	60.5589202919276
1981-01-01	61.7579770893242
1982-01-01	62.6750784308451
1983-01-01	63.4150327895811
1984-01-01	64.1591608874421
1985-01-01	64.9712600103005
1986-01-01	65.5895056759448
1987-01-01	66.3096701155949
1988-01-01	67.0281018017355
1989-01-01	67.6022306374791
1990-01-01	67.9820254636115
1991-01-01	68.1617392274737
1992-01-01	68.2700566448745
1993-01-01	68.3003501438513
1994-01-01	68.2762910939825
1995-01-01	68.2245522046814
1996-01-01	68.3167302435213
1997-01-01	68.2893736080762
1998-01-01	68.2285684950159
1999-01-01	68.2383102652348
2000-01-01	68.3589047395616
2001-01-01	68.4900034344841
2002-01-01	68.7576517663847
2003-01-01	69.1002086726543
2004-01-01	69.4125672620457
2005-01-01	69.6417299399437
2006-01-01	69.8646265529403
2007-01-01	70.0009120917803
2008-01-01	70.0679077546691
2009-01-01	70.1072888683603
2010-01-01	70.1334795016805
2011-01-01	70.1458283482249
2012-01-01	70.1339360784864
2013-01-01	70.0842004853241
2014-01-01	69.9780249020806
2015-01-01	69.8065302834759
2016-01-01	69.5327772385840
2017-01-01	69.2283760669472