Year	Percent of Total
1960-01-01	43.1416580043689
1961-01-01	43.3003491793463
1962-01-01	43.4320652037641
1963-01-01	43.5107980989530
1964-01-01	43.5003517490878
1965-01-01	43.3855269861489
1966-01-01	43.3531199932095
1967-01-01	43.1647467851109
1968-01-01	42.8722302657692
1969-01-01	42.5403242814510
1970-01-01	42.1974418042155
1971-01-01	41.8516543934198
1972-01-01	41.5047010793441
1973-01-01	41.1415499751336
1974-01-01	40.7397210263958
1975-01-01	40.2987926078945
1976-01-01	39.9144949054233
1977-01-01	39.5173393327261
1978-01-01	39.1143015697955
1979-01-01	38.7186735234353
1980-01-01	38.3406632834147
1981-01-01	38.1037007324013
1982-01-01	37.8472140796306
1983-01-01	37.5841997772738
1984-01-01	37.3176820384449
1985-01-01	37.0393377748908
1986-01-01	36.8042399066613
1987-01-01	36.5204227137083
1988-01-01	36.1970679452863
1989-01-01	35.8428761010460
1990-01-01	35.4596326688177
1991-01-01	34.9928331390172
1992-01-01	34.5346788343941
1993-01-01	34.0618019871894
1994-01-01	33.5506319355829
1995-01-01	32.9991047502581
1996-01-01	32.4506762359127
1997-01-01	31.8784145867678
1998-01-01	31.2913343923488
1999-01-01	30.7032081635134
2000-01-01	30.1202417715979
2001-01-01	29.6098017520834
2002-01-01	29.0658219472428
2003-01-01	28.5107925816897
2004-01-01	27.9685110287107
2005-01-01	27.4462905561779
2006-01-01	26.9010476412523
2007-01-01	26.3930380557346
2008-01-01	25.9036623093383
2009-01-01	25.4087251746311
2010-01-01	24.9017800230755
2011-01-01	24.3996044667069
2012-01-01	23.9107723160691
2013-01-01	23.4323030254955
2014-01-01	22.9648202890066
2015-01-01	22.5102794150854
2016-01-01	22.1362691046907
2017-01-01	21.7471410415064