Year	Percent of Total
1960-01-01	42.9611145242083
1961-01-01	43.1976067995138
1962-01-01	43.3536401995344
1963-01-01	43.4595321382259
1964-01-01	43.5777489917711
1965-01-01	43.7772952599451
1966-01-01	44.0615119595001
1967-01-01	44.2890157709053
1968-01-01	44.4923372632055
1969-01-01	44.6562422754455
1970-01-01	44.7384144433383
1971-01-01	45.0390774053811
1972-01-01	45.2966343385914
1973-01-01	45.4956595733596
1974-01-01	45.6332835728428
1975-01-01	45.7157721019264
1976-01-01	45.9646453272630
1977-01-01	46.1324420324899
1978-01-01	46.2409600115507
1979-01-01	46.3227520634952
1980-01-01	46.4084423958933
1981-01-01	46.5600583775687
1982-01-01	46.6381550194747
1983-01-01	46.6658603850722
1984-01-01	46.6466384543587
1985-01-01	46.5715891268167
1986-01-01	46.6353053786838
1987-01-01	46.6396571178557
1988-01-01	46.5793840635546
1989-01-01	46.4441878236413
1990-01-01	46.2296207492065
1991-01-01	46.2333773196153
1992-01-01	46.1326490369406
1993-01-01	45.9533088671233
1994-01-01	45.7356083928445
1995-01-01	45.5060383376415
1996-01-01	45.0740046354927
1997-01-01	44.6487425105595
1998-01-01	44.2304942719880
1999-01-01	43.8113485617850
2000-01-01	43.3929929117910
2001-01-01	43.2259471768096
2002-01-01	43.0551662467209
2003-01-01	42.8871271122293
2004-01-01	42.7340883655868
2005-01-01	42.6036745055838
2006-01-01	42.6177911100635
2007-01-01	42.6098041062897
2008-01-01	42.5899039825402
2009-01-01	42.5623871332185
2010-01-01	42.5233801510452
2011-01-01	42.4995231523388
2012-01-01	42.4449542982983
2013-01-01	42.3539546224110
2014-01-01	42.2171238699030
2015-01-01	42.0303251994593
2016-01-01	41.8253690917644
2017-01-01	41.5815752708429