Year	Percent of Total
1960-01-01	38.5320169006531
1961-01-01	38.9725804351978
1962-01-01	39.4207749742698
1963-01-01	39.8674484114141
1964-01-01	40.2780780095632
1965-01-01	40.6353092058977
1966-01-01	41.0935742437343
1967-01-01	41.4645595540098
1968-01-01	41.7682037835069
1969-01-01	42.0287435089616
1970-01-01	42.2589052102433
1971-01-01	42.6536969372822
1972-01-01	42.9727356092375
1973-01-01	43.2319044216240
1974-01-01	43.4462818110743
1975-01-01	43.6268304970805
1976-01-01	43.9393780960829
1977-01-01	44.1927175639352
1978-01-01	44.3959854004242
1979-01-01	44.5552415541577
1980-01-01	44.6758483952152
1981-01-01	44.9291489709245
1982-01-01	45.1072812327985
1983-01-01	45.2309670245837
1984-01-01	45.3210014677088
1985-01-01	45.3879057174464
1986-01-01	45.5594112029817
1987-01-01	45.6769100270481
1988-01-01	45.7497904919736
1989-01-01	45.7855326621322
1990-01-01	45.7908573191582
1991-01-01	45.7942996007961
1992-01-01	45.7446195967856
1993-01-01	45.6548931926271
1994-01-01	45.5310786074040
1995-01-01	45.3741035140117
1996-01-01	45.4230776867212
1997-01-01	45.4122562598710
1998-01-01	45.3536601669329
1999-01-01	45.2598836331639
2000-01-01	45.1387579084092
2001-01-01	45.0684941766208
2002-01-01	44.9554746460575
2003-01-01	44.8081025934921
2004-01-01	44.6337834148215
2005-01-01	44.4385243462819
2006-01-01	44.3714268745765
2007-01-01	44.2777118913998
2008-01-01	44.1583430264245
2009-01-01	44.0137439956104
2010-01-01	43.8460097710044
2011-01-01	43.7447903465266
2012-01-01	43.6034354456089
2013-01-01	43.4320883774632
2014-01-01	43.2416500043940
2015-01-01	43.0370901834653
2016-01-01	42.8658596370335
2017-01-01	42.6681318704918