Year	Percent of Total
1960-01-01	65.4311281311344
1961-01-01	65.3560092317095
1962-01-01	65.3470474360848
1963-01-01	65.3662035303552
1964-01-01	65.3464411274984
1965-01-01	65.2604675813781
1966-01-01	65.0680664417965
1967-01-01	64.8795547274882
1968-01-01	64.6822533065141
1969-01-01	64.4691354451803
1970-01-01	64.2431151209894
1971-01-01	64.0902536852226
1972-01-01	63.9281618002138
1973-01-01	63.7840991070162
1974-01-01	63.6994913582001
1975-01-01	63.6980588025880
1976-01-01	63.6804460778357
1977-01-01	63.7613566877562
1978-01-01	63.9543732475992
1979-01-01	64.2694162156780
1980-01-01	64.7058563918525
1981-01-01	65.2438510516663
1982-01-01	65.8837331459048
1983-01-01	66.5651776717174
1984-01-01	67.2067195554720
1985-01-01	67.7533054591398
1986-01-01	68.0615945022817
1987-01-01	68.2867067682959
1988-01-01	68.4468686198767
1989-01-01	68.5715685942009
1990-01-01	68.6768876148491
1991-01-01	68.6741945009035
1992-01-01	68.6536197146134
1993-01-01	68.6085749528537
1994-01-01	68.5375949189126
1995-01-01	68.4415088776314
1996-01-01	68.2938622571124
1997-01-01	68.1423650624139
1998-01-01	67.9750834042621
1999-01-01	67.7737818382581
2000-01-01	67.5266928464988
2001-01-01	67.3225401284696
2002-01-01	67.0734645239108
2003-01-01	66.8069311941037
2004-01-01	66.5641268994198
2005-01-01	66.3654646558388
2006-01-01	66.1461165392902
2007-01-01	65.9866248686577
2008-01-01	65.8545233102841
2009-01-01	65.6991659866772
2010-01-01	65.4910922447816
2011-01-01	65.2005008238882
2012-01-01	64.8822391008754
2013-01-01	64.5451380974727
2014-01-01	64.2148595195744
2015-01-01	63.9104186439777
2016-01-01	63.6824995509839
2017-01-01	63.4612305613722