Year	Percent of Total
1960-01-01	38.4249112774929
1961-01-01	39.2214401732539
1962-01-01	39.9724030419853
1963-01-01	40.7064682734875
1964-01-01	41.4403177200790
1965-01-01	42.1540198120001
1966-01-01	43.1343283582090
1967-01-01	44.0904610463278
1968-01-01	44.9676697678226
1969-01-01	45.6986622400156
1970-01-01	46.2502591389676
1971-01-01	46.4633349528389
1972-01-01	46.4715937168364
1973-01-01	46.3272061412776
1974-01-01	46.0902454707062
1975-01-01	45.7928932969037
1976-01-01	45.7939075107525
1977-01-01	45.6831748839266
1978-01-01	45.5242726271391
1979-01-01	45.4037526240987
1980-01-01	45.3742462985762
1981-01-01	45.4295909964315
1982-01-01	45.6301482701812
1983-01-01	45.8923994647191
1984-01-01	46.1167622285505
1985-01-01	46.2573232016959
1986-01-01	46.7780624067388
1987-01-01	47.0889702841614
1988-01-01	47.2682659551659
1989-01-01	47.4041413698377
1990-01-01	47.5075599758081
1991-01-01	47.5199561269880
1992-01-01	47.4867691265507
1993-01-01	47.3523358588462
1994-01-01	47.0340091694743
1995-01-01	46.4838123125605
1996-01-01	45.6088259224840
1997-01-01	44.5717529089017
1998-01-01	43.3846199564646
1999-01-01	42.0938925401845
2000-01-01	40.7416257703721
2001-01-01	38.7921693777937
2002-01-01	36.8586095718911
2003-01-01	34.9827437303323
2004-01-01	33.2059802269806
2005-01-01	31.5623078949680
2006-01-01	30.0921584379802
2007-01-01	28.6993781057518
2008-01-01	27.4394732418694
2009-01-01	26.3570483581147
2010-01-01	25.4697389104856
2011-01-01	24.7740122783774
2012-01-01	24.2517536114427
2013-01-01	23.8897123028105
2014-01-01	23.6273628465120
2015-01-01	23.4102049937500
2016-01-01	23.4332189378992
2017-01-01	23.4095753214310