Year	Percent of Total
1960-01-01	52.6670667022080
1961-01-01	52.4575803670559
1962-01-01	52.3412720904134
1963-01-01	52.2913891661576
1964-01-01	52.2593910170317
1965-01-01	52.2198242391461
1966-01-01	52.0880985837098
1967-01-01	51.9694043923287
1968-01-01	51.8698606442217
1969-01-01	51.7987381609956
1970-01-01	51.7581917622574
1971-01-01	51.6016361089589
1972-01-01	51.4753702361707
1973-01-01	51.3810968537210
1974-01-01	51.3174742293267
1975-01-01	51.2819443177028
1976-01-01	51.2466909605051
1977-01-01	51.2634219222183
1978-01-01	51.3207040323255
1979-01-01	51.4078499964360
1980-01-01	51.5217713213619
1981-01-01	51.3776243032247
1982-01-01	51.2712128978485
1983-01-01	51.2085953380472
1984-01-01	51.2005169836335
1985-01-01	51.2581239403556
1986-01-01	51.3059543517699
1987-01-01	51.3912524746634
1988-01-01	51.4925864144254
1989-01-01	51.5988355492499
1990-01-01	51.7168369350935
1991-01-01	52.0788098257773
1992-01-01	52.4351261846021
1993-01-01	52.7816429677916
1994-01-01	53.1261816231656
1995-01-01	53.4779110902434
1996-01-01	53.5711667999237
1997-01-01	53.6784440137358
1998-01-01	53.8120502506965
1999-01-01	53.9913765105832
2000-01-01	54.2358079069984
2001-01-01	54.4693272108825
2002-01-01	54.8017359928340
2003-01-01	55.2011186087044
2004-01-01	55.6244208078903
2005-01-01	56.0468786787468
2006-01-01	56.5805311391277
2007-01-01	57.0624233524207
2008-01-01	57.5026125914407
2009-01-01	57.9222358854383
2010-01-01	58.3241487225754
2011-01-01	58.6721707459575
2012-01-01	59.0147603171018
2013-01-01	59.3439191521899
2014-01-01	59.6436735274037
2015-01-01	59.9077090743547
2016-01-01	59.9923496509018
2017-01-01	60.1029221269140