Year	Percent of Total
1960-01-01	45.7430225588349
1961-01-01	45.9630530485619
1962-01-01	46.2956189638273
1963-01-01	46.6352358852974
1964-01-01	46.8241986245778
1965-01-01	46.7899617098412
1966-01-01	46.7815864679170
1967-01-01	46.5665149063149
1968-01-01	46.2101785247752
1969-01-01	45.8422975748286
1970-01-01	45.5434056608521
1971-01-01	45.2608938756462
1972-01-01	45.0838283915184
1973-01-01	44.9462455109480
1974-01-01	44.6709148230136
1975-01-01	44.1134991617917
1976-01-01	43.6662901011540
1977-01-01	42.8963625124908
1978-01-01	41.9527612849910
1979-01-01	41.2290411013952
1980-01-01	41.0670959086578
1981-01-01	40.5204178363008
1982-01-01	40.7808877031428
1983-01-01	41.5031117837080
1984-01-01	42.1329035018578
1985-01-01	42.4284887108455
1986-01-01	43.3664581976375
1987-01-01	43.5942761117355
1988-01-01	43.5226810032680
1989-01-01	43.6877729840610
1990-01-01	44.2848495020027
1991-01-01	44.6271423550572
1992-01-01	45.3303142627182
1993-01-01	46.1107262791205
1994-01-01	46.5523408938268
1995-01-01	46.4761913343880
1996-01-01	46.2824467114798
1997-01-01	45.5555211280573
1998-01-01	44.3701483539162
1999-01-01	42.9794635244634
2000-01-01	41.5907897350587
2001-01-01	40.3384067032438
2002-01-01	39.3328341272694
2003-01-01	38.5361255364843
2004-01-01	37.8159720874625
2005-01-01	37.0659947049785
2006-01-01	36.2418122126932
2007-01-01	35.4293249106344
2008-01-01	34.6329734738114
2009-01-01	33.9161068452645
2010-01-01	33.3265961922573
2011-01-01	32.9205773108965
2012-01-01	32.4947184335298
2013-01-01	32.1090121530815
2014-01-01	31.8101028172085
2015-01-01	31.6021610251820
2016-01-01	31.3909266182687
2017-01-01	31.2784962899646