Year	Percent of Total
1960-01-01	52.7196712776586
1961-01-01	52.2326692883603
1962-01-01	51.6354841860663
1963-01-01	51.0570918382447
1964-01-01	50.7038936566775
1965-01-01	50.6604308449423
1966-01-01	50.3589037318318
1967-01-01	50.3886908719336
1968-01-01	50.6310824488399
1969-01-01	50.9052134756223
1970-01-01	51.1090359293552
1971-01-01	51.0046744250873
1972-01-01	50.9089289474567
1973-01-01	50.8174818218292
1974-01-01	50.7584350614061
1975-01-01	50.7423840663931
1976-01-01	50.4491648332483
1977-01-01	50.2530073836045
1978-01-01	50.1241919464881
1979-01-01	50.0327546504834
1980-01-01	49.9623512021411
1981-01-01	49.6635136952138
1982-01-01	49.4769444371392
1983-01-01	49.3711865263490
1984-01-01	49.3284971832640
1985-01-01	49.3520904149498
1986-01-01	49.1737094197190
1987-01-01	49.0557900738332
1988-01-01	49.0115136675732
1989-01-01	49.0512872955873
1990-01-01	49.1645483883133
1991-01-01	49.0642489719556
1992-01-01	49.1035980304349
1993-01-01	49.2343402219113
1994-01-01	49.4135558499884
1995-01-01	49.6288175606493
1996-01-01	49.6234509562681
1997-01-01	49.6859860848125
1998-01-01	49.8037578950587
1999-01-01	49.9597423560948
2000-01-01	50.1307347445922
2001-01-01	50.1233449443706
2002-01-01	50.1638142319920
2003-01-01	50.2322564575821
2004-01-01	50.3162986233865
2005-01-01	50.4098239502567
2006-01-01	50.3286851670427
2007-01-01	50.2929298831819
2008-01-01	50.2908487450493
2009-01-01	50.3171527126465
2010-01-01	50.3702426932349
2011-01-01	50.3271560474372
2012-01-01	50.3499580612962
2013-01-01	50.4160765648884
2014-01-01	50.5056636092406
2015-01-01	50.6133839304319
2016-01-01	50.6908628095137
2017-01-01	50.7875838704107