Year	Percent of Total
1960-01-01	44.6277406365062
1961-01-01	45.2053589106188
1962-01-01	45.7169540854003
1963-01-01	46.1782246062592
1964-01-01	46.6639947687051
1965-01-01	47.2212415110797
1966-01-01	47.5475322074764
1967-01-01	47.9970259326615
1968-01-01	48.6187845303867
1969-01-01	49.3571713593320
1970-01-01	50.0777649769585
1971-01-01	49.4126577474144
1972-01-01	48.7633272274670
1973-01-01	48.0821841326559
1974-01-01	47.3777319131685
1975-01-01	46.6798458581202
1976-01-01	46.1072944392490
1977-01-01	45.5495386906081
1978-01-01	44.9924047980724
1979-01-01	44.4199845214550
1980-01-01	43.8378804444557
1981-01-01	42.9319196615215
1982-01-01	42.1397560130082
1983-01-01	41.4836239204823
1984-01-01	40.9992929909696
1985-01-01	40.6809156923856
1986-01-01	39.4350756886619
1987-01-01	38.4381152983195
1988-01-01	37.6551114705728
1989-01-01	37.0369825531790
1990-01-01	36.5437637949126
1991-01-01	36.0748023630811
1992-01-01	35.7421173154835
1993-01-01	35.4884547069272
1994-01-01	35.2461668743589
1995-01-01	34.9834063273578
1996-01-01	34.6319561890956
1997-01-01	34.1739141945647
1998-01-01	33.6173074035631
1999-01-01	32.9711545897456
2000-01-01	32.2493293999962
2001-01-01	31.4771809369952
2002-01-01	30.6053341512115
2003-01-01	29.6565262497437
2004-01-01	28.6802546671515
2005-01-01	27.7172385990202
2006-01-01	26.6881087257492
2007-01-01	25.7543876428674
2008-01-01	24.8676279399598
2009-01-01	24.0033445989405
2010-01-01	23.1672267933712
2011-01-01	22.4095678586221
2012-01-01	21.7044642091115
2013-01-01	21.0269839462598
2014-01-01	20.3705908026822
2015-01-01	19.7442524519486
2016-01-01	19.3185967474651
2017-01-01	18.8834962313525