Year	Percent of Total
1960-01-01	46.2964716131415
1961-01-01	46.6645074167373
1962-01-01	46.9847173848098
1963-01-01	47.2432306118941
1964-01-01	47.4137133258335
1965-01-01	47.4914429179756
1966-01-01	47.6684886204156
1967-01-01	47.7559247977208
1968-01-01	47.7746358748902
1969-01-01	47.7475974562439
1970-01-01	47.6872879518556
1971-01-01	47.7565512620058
1972-01-01	47.7419865216943
1973-01-01	47.6808642927537
1974-01-01	47.6134050981056
1975-01-01	47.5568942754818
1976-01-01	47.5507188515600
1977-01-01	47.5601692299204
1978-01-01	47.5635203568198
1979-01-01	47.5245362264188
1980-01-01	47.4286121307587
1981-01-01	47.4052304572339
1982-01-01	47.3023842285324
1983-01-01	47.1491304771678
1984-01-01	46.9807482128876
1985-01-01	46.8111312067746
1986-01-01	46.6579882172022
1987-01-01	46.4912180270219
1988-01-01	46.3091493578019
1989-01-01	46.1047951065788
1990-01-01	45.8751065519780
1991-01-01	45.6152421856602
1992-01-01	45.3503120143236
1993-01-01	45.0697330242526
1994-01-01	44.7599108529749
1995-01-01	44.4157881931691
1996-01-01	44.0782133282571
1997-01-01	43.6847163371252
1998-01-01	43.2559391707981
1999-01-01	42.8183792886860
2000-01-01	42.3823430099522
2001-01-01	41.9195342758717
2002-01-01	41.4605552517595
2003-01-01	40.9890015682799
2004-01-01	40.4775134564743
2005-01-01	39.9127543083748
2006-01-01	39.3370413951987
2007-01-01	38.7033450562612
2008-01-01	38.0264835586660
2009-01-01	37.3279671577710
2010-01-01	36.6186124871229
2011-01-01	35.8958762392835
2012-01-01	35.1680871740959
2013-01-01	34.4372145993461
2014-01-01	33.7085388756502
2015-01-01	32.9910882129321
2016-01-01	32.2988034391372
2017-01-01	31.6440992817429