Year	Percent of Total
1960-01-01	43.1438598288847
1961-01-01	43.3069402624438
1962-01-01	43.9420927424657
1963-01-01	44.8161497978972
1964-01-01	45.5598455598456
1965-01-01	45.9802221794131
1966-01-01	46.0023570276641
1967-01-01	45.9236821321817
1968-01-01	45.8224517826398
1969-01-01	45.7602216045743
1970-01-01	45.6898502194669
1971-01-01	45.4209057587501
1972-01-01	44.8634161600960
1973-01-01	44.1735591225604
1974-01-01	43.5083724680992
1975-01-01	42.9302015786371
1976-01-01	42.2061922997002
1977-01-01	41.6681069247609
1978-01-01	41.1970747804687
1979-01-01	40.6338257658049
1980-01-01	39.9056081419569
1981-01-01	39.3681636937335
1982-01-01	38.6386803242007
1983-01-01	37.7893039797600
1984-01-01	36.9756332308270
1985-01-01	36.3136686377023
1986-01-01	35.9389143412467
1987-01-01	35.7496620708300
1988-01-01	35.7118763768987
1989-01-01	35.6948705804831
1990-01-01	35.5856332703214
1991-01-01	35.5788650403928
1992-01-01	35.3560745569164
1993-01-01	34.9962802083083
1994-01-01	34.6282003412437
1995-01-01	34.3082585178163
1996-01-01	33.7326650948774
1997-01-01	33.3328863680044
1998-01-01	32.9653728938242
1999-01-01	32.4581888114290
2000-01-01	31.7523539775266
2001-01-01	31.0855338143928
2002-01-01	30.2249740822674
2003-01-01	29.2826128072950
2004-01-01	28.4297487836362
2005-01-01	27.7331826777461
2006-01-01	27.1358869341277
2007-01-01	26.6141967965494
2008-01-01	26.1308843030789
2009-01-01	25.6562028157135
2010-01-01	25.2027481144052
2011-01-01	24.8314760805357
2012-01-01	24.5753635403363
2013-01-01	24.3748354830219
2014-01-01	24.1665577674202
2015-01-01	23.9256004897548
2016-01-01	23.6338719808142
2017-01-01	23.2845830668499