Year	Percent of Total
1960-01-01	42.9564808872634
1961-01-01	43.2204493253623
1962-01-01	43.4651689593866
1963-01-01	43.6873098702233
1964-01-01	43.8560690145299
1965-01-01	43.9630236631063
1966-01-01	44.3403286322619
1967-01-01	44.6022241011366
1968-01-01	44.7861821793901
1969-01-01	44.9370332486007
1970-01-01	45.0843746035924
1971-01-01	45.1954962442543
1972-01-01	45.2356438528983
1973-01-01	45.2304026929783
1974-01-01	45.1991320934321
1975-01-01	45.1607895095625
1976-01-01	45.3513818178352
1977-01-01	45.4815040445159
1978-01-01	45.5603767720014
1979-01-01	45.5863223362829
1980-01-01	45.5619854889419
1981-01-01	45.7328247032539
1982-01-01	45.7816392397877
1983-01-01	45.7432105293790
1984-01-01	45.6508232449340
1985-01-01	45.5211503813429
1986-01-01	45.5523387500521
1987-01-01	45.5367052913019
1988-01-01	45.4648616190458
1989-01-01	45.3228977562163
1990-01-01	45.1138162698730
1991-01-01	44.9905932395951
1992-01-01	44.7904770174684
1993-01-01	44.5353505108484
1994-01-01	44.2555605945095
1995-01-01	43.9716467159349
1996-01-01	43.9433383200239
1997-01-01	43.9007648977540
1998-01-01	43.8375095501592
1999-01-01	43.7408778144460
2000-01-01	43.6060611890012
2001-01-01	43.7868981450400
2002-01-01	43.9200157406347
2003-01-01	44.0123579169036
2004-01-01	44.0806283545188
2005-01-01	44.1343601270114
2006-01-01	44.0960970211132
2007-01-01	44.0444775554949
2008-01-01	43.9696387103776
2009-01-01	43.8637613294218
2010-01-01	43.7328574297432
2011-01-01	43.5571310711767
2012-01-01	43.3573282066996
2013-01-01	43.1407056405281
2014-01-01	42.9189551447206
2015-01-01	42.7024859107950
2016-01-01	42.5759811214750
2017-01-01	42.4327848609268