Year	Percent of Total
1960-01-01	64.1153029057328
1961-01-01	64.8618431867862
1962-01-01	65.6849308761539
1963-01-01	66.5337278460962
1964-01-01	67.3141202684974
1965-01-01	67.9673343430001
1966-01-01	68.3559671714062
1967-01-01	68.6886069980089
1968-01-01	68.9256059328040
1969-01-01	69.0345556411983
1970-01-01	69.0110925694095
1971-01-01	68.9206329372773
1972-01-01	68.6871669077719
1973-01-01	68.3735234273676
1974-01-01	68.0871593237011
1975-01-01	67.8922566194274
1976-01-01	67.5930521589442
1977-01-01	67.4754621944160
1978-01-01	67.4778508610782
1979-01-01	67.5012563952783
1980-01-01	67.5017155396555
1981-01-01	67.6939450333063
1982-01-01	67.7805049948993
1983-01-01	67.8391064115789
1984-01-01	67.9814832036149
1985-01-01	68.2461934684615
1986-01-01	68.4399340278897
1987-01-01	68.7645735256894
1988-01-01	69.1482949370560
1989-01-01	69.4676731364345
1990-01-01	69.6566086225961
1991-01-01	69.7716948409203
1992-01-01	69.7842843337827
1993-01-01	69.7101089900562
1994-01-01	69.5933064480829
1995-01-01	69.4567844363082
1996-01-01	69.2714469760103
1997-01-01	69.0432384111068
1998-01-01	68.7870568127144
1999-01-01	68.5156156092340
2000-01-01	68.2321883052710
2001-01-01	67.9139924690296
2002-01-01	67.6033720248273
2003-01-01	67.2819569297805
2004-01-01	66.9246566542940
2005-01-01	66.5176871541976
2006-01-01	66.1349590588848
2007-01-01	65.7143629095748
2008-01-01	65.2491377163597
2009-01-01	64.7290748995818
2010-01-01	64.1463637017564
2011-01-01	63.5369452453900
2012-01-01	62.8870380715539
2013-01-01	62.2225789889280
2014-01-01	61.5826784719472
2015-01-01	60.9934148210465
2016-01-01	60.4996889474557
2017-01-01	60.0646125860840