Year	Percent of Total
1960-01-01	42.1368397031196
1961-01-01	42.4451420370373
1962-01-01	42.6182565386115
1963-01-01	42.7152574891803
1964-01-01	42.8060782042717
1965-01-01	42.9193531281752
1966-01-01	43.2533769830791
1967-01-01	43.5515293614059
1968-01-01	43.8169878651640
1969-01-01	44.0388383432089
1970-01-01	44.2134695077522
1971-01-01	44.5539146028250
1972-01-01	44.8087091385897
1973-01-01	44.9953033890924
1974-01-01	45.1228543572594
1975-01-01	45.1822142880630
1976-01-01	45.4477968153234
1977-01-01	45.6787345864232
1978-01-01	45.8645867940842
1979-01-01	45.9691831818494
1980-01-01	45.9448822760838
1981-01-01	46.2173836371723
1982-01-01	46.4547287395061
1983-01-01	46.6690891932365
1984-01-01	46.9120615184631
1985-01-01	47.2591561607563
1986-01-01	47.4295970508164
1987-01-01	47.4972139297687
1988-01-01	47.5446083524942
1989-01-01	47.6863427882518
1990-01-01	48.0414420177655
1991-01-01	48.0147121014507
1992-01-01	47.9736798569454
1993-01-01	47.9606592841822
1994-01-01	47.9296462147150
1995-01-01	47.7977215879654
1996-01-01	47.9960931126522
1997-01-01	48.1935173778351
1998-01-01	48.3468961167778
1999-01-01	48.4608122708295
2000-01-01	48.5695854971067
2001-01-01	48.4935871157667
2002-01-01	48.3209836540374
2003-01-01	48.0982469819554
2004-01-01	47.8472534015640
2005-01-01	47.5621198814653
2006-01-01	47.6936174978614
2007-01-01	47.8235882070236
2008-01-01	47.9107794667633
2009-01-01	47.9094715742362
2010-01-01	47.7981119229007
2011-01-01	47.3432759316587
2012-01-01	46.7391003369129
2013-01-01	46.0337849029651
2014-01-01	45.2873891645466
2015-01-01	44.5319836732294
2016-01-01	43.8595249450370
2017-01-01	43.2445594480913