Year	Percent of Total
1960-01-01	45.4742159780687
1961-01-01	45.7501253198328
1962-01-01	46.0269659483148
1963-01-01	46.2379447306266
1964-01-01	46.3033513317484
1965-01-01	46.1923675936432
1966-01-01	46.0475821099569
1967-01-01	45.6698033838162
1968-01-01	45.1608649264052
1969-01-01	44.6656560395995
1970-01-01	44.2541904472593
1971-01-01	43.6312649279022
1972-01-01	43.1847104060127
1973-01-01	42.8300297307840
1974-01-01	42.4416402238925
1975-01-01	41.9708282161148
1976-01-01	41.5342404494128
1977-01-01	41.0062557141814
1978-01-01	40.4371035464341
1979-01-01	39.9166476042966
1980-01-01	39.4909815645242
1981-01-01	39.1451438533336
1982-01-01	38.8814297204552
1983-01-01	38.6794732598865
1984-01-01	38.4994297845030
1985-01-01	38.3208489396268
1986-01-01	38.1277661573693
1987-01-01	37.8959459750581
1988-01-01	37.6245185166566
1989-01-01	37.3337068132697
1990-01-01	37.0411303801501
1991-01-01	36.7498902018376
1992-01-01	36.4691350907950
1993-01-01	36.1901971929473
1994-01-01	35.8979189062593
1995-01-01	35.5826766109814
1996-01-01	35.1957048080082
1997-01-01	34.7980102317030
1998-01-01	34.3719328640687
1999-01-01	33.8977138618395
2000-01-01	33.3703131701355
2001-01-01	32.9357974188430
2002-01-01	32.3784503296464
2003-01-01	31.7427043453842
2004-01-01	31.0895293255463
2005-01-01	30.4574975721366
2006-01-01	29.9911228636522
2007-01-01	29.5194161912983
2008-01-01	29.0262291022165
2009-01-01	28.4937325448446
2010-01-01	27.9312154197049
2011-01-01	27.2424764436185
2012-01-01	26.5951310462887
2013-01-01	26.0013120261931
2014-01-01	25.4598639401321
2015-01-01	24.9638293983805
2016-01-01	24.6214889314597
2017-01-01	24.3136535920646