Year	Percent of Total
1960-01-01	65.5989128348067
1961-01-01	65.3905985316312
1962-01-01	65.4375628568677
1963-01-01	65.6281430414531
1964-01-01	65.7617404924055
1965-01-01	65.7380435533786
1966-01-01	65.6063187008715
1967-01-01	65.2450949052472
1968-01-01	64.7357093699088
1969-01-01	64.2148421131850
1970-01-01	63.7468438918011
1971-01-01	63.5376726090000
1972-01-01	63.4803263670446
1973-01-01	63.5209813903324
1974-01-01	63.5595034246575
1975-01-01	63.5434044508956
1976-01-01	63.6372702609549
1977-01-01	63.6481592327922
1978-01-01	63.6400030536260
1979-01-01	63.7089263314258
1980-01-01	63.8942284937554
1981-01-01	63.9963983353146
1982-01-01	64.2258097221120
1983-01-01	64.5285102776776
1984-01-01	64.8361575908162
1985-01-01	65.1276289033728
1986-01-01	65.4617896129587
1987-01-01	65.8011134174741
1988-01-01	66.1297470415989
1989-01-01	66.4330718312228
1990-01-01	66.6920166263731
1991-01-01	67.0467260729468
1992-01-01	67.3417585385790
1993-01-01	67.5972820462652
1994-01-01	67.8417264571095
1995-01-01	68.0818305045473
1996-01-01	68.0862780619860
1997-01-01	68.1313675615172
1998-01-01	68.1834636354299
1999-01-01	68.2003028601839
2000-01-01	68.1659835081639
2001-01-01	67.9608325812440
2002-01-01	67.7246333824829
2003-01-01	67.4782833597203
2004-01-01	67.2640978074041
2005-01-01	67.1046996408524
2006-01-01	67.0010768363764
2007-01-01	66.9299001651627
2008-01-01	66.8763053709103
2009-01-01	66.8156057570946
2010-01-01	66.7316150919032
2011-01-01	66.4728497072304
2012-01-01	66.2318050998497
2013-01-01	65.9980125957266
2014-01-01	65.7568413115419
2015-01-01	65.5062044251101
2016-01-01	65.4626512332753
2017-01-01	65.3892243148673