Year	Percent of Total
1960-01-01	66.3312334942822
1961-01-01	66.4559008763320
1962-01-01	66.6649838071518
1963-01-01	66.9210688947668
1964-01-01	67.1572897433867
1965-01-01	67.3383302097788
1966-01-01	67.4398126101854
1967-01-01	67.5092141836403
1968-01-01	67.5442822722457
1969-01-01	67.5497702348134
1970-01-01	67.5251743290254
1971-01-01	67.4259677101258
1972-01-01	67.3166437651788
1973-01-01	67.1897994309860
1974-01-01	67.0396690982866
1975-01-01	66.8682605353567
1976-01-01	66.6028234712087
1977-01-01	66.3346544518589
1978-01-01	66.1065218066034
1979-01-01	65.9850063033798
1980-01-01	66.0019315727676
1981-01-01	66.0839012027868
1982-01-01	66.3290361944808
1983-01-01	66.6462155903101
1984-01-01	66.9016316016223
1985-01-01	67.0234758962133
1986-01-01	67.0247286449248
1987-01-01	66.8697363263899
1988-01-01	66.6530521765821
1989-01-01	66.5099512826490
1990-01-01	66.5095379438325
1991-01-01	66.3986316698396
1992-01-01	66.4592266491383
1993-01-01	66.6366717199815
1994-01-01	66.8312119328790
1995-01-01	66.9857313006762
1996-01-01	67.1330551171074
1997-01-01	67.2436342858980
1998-01-01	67.3463459089231
1999-01-01	67.5037185986211
2000-01-01	67.7471030423791
2001-01-01	67.9727095713208
2002-01-01	68.2356256974562
2003-01-01	68.5254298470210
2004-01-01	68.8113436400980
2005-01-01	69.0619296821102
2006-01-01	69.0554270521323
2007-01-01	69.0569078766092
2008-01-01	69.0170646273779
2009-01-01	68.8780892780742
2010-01-01	68.6146835949053
2011-01-01	68.1543071142720
2012-01-01	67.6203695483534
2013-01-01	67.0372072328351
2014-01-01	66.4564198032579
2015-01-01	65.9170261749526
2016-01-01	65.4326148209618
2017-01-01	64.9624938475456