Year	Percent of Total
1960-01-01	40.1549213474356
1961-01-01	40.5409573521561
1962-01-01	40.8998045629600
1963-01-01	41.2118954457162
1964-01-01	41.4324636728389
1965-01-01	41.5320719889248
1966-01-01	41.6419676709699
1967-01-01	41.5998855251907
1968-01-01	41.4360874332833
1969-01-01	41.1976169395610
1970-01-01	40.9100166558325
1971-01-01	40.5409995753928
1972-01-01	40.1786902731511
1973-01-01	39.7897140636851
1974-01-01	39.3287068739259
1975-01-01	38.7846197934746
1976-01-01	38.2957112991086
1977-01-01	37.7097406063533
1978-01-01	37.0800785426833
1979-01-01	36.4810230112029
1980-01-01	35.9488654312428
1981-01-01	35.4616940046334
1982-01-01	35.0365489683013
1983-01-01	34.6597017403638
1984-01-01	34.3109231070392
1985-01-01	33.9873493240861
1986-01-01	33.7098533479206
1987-01-01	33.4762101869200
1988-01-01	33.2638634098066
1989-01-01	33.0214073030462
1990-01-01	32.6958720128333
1991-01-01	32.8121703678081
1992-01-01	32.8555289520078
1993-01-01	32.8165782172779
1994-01-01	32.7353256309712
1995-01-01	32.6548506213595
1996-01-01	32.1327858101020
1997-01-01	31.6669581812850
1998-01-01	31.2344482931826
1999-01-01	30.7807288283130
2000-01-01	30.2632312289996
2001-01-01	29.6036584584718
2002-01-01	28.8756532882509
2003-01-01	28.0905688033288
2004-01-01	27.2817631652940
2005-01-01	26.4677370169126
2006-01-01	25.5476894940332
2007-01-01	24.7012226235794
2008-01-01	23.9078355062138
2009-01-01	23.1620162456732
2010-01-01	22.4667363821086
2011-01-01	21.4253522532007
2012-01-01	20.4707882326229
2013-01-01	19.5826415957914
2014-01-01	18.7599181724029
2015-01-01	18.0268746288507
2016-01-01	17.7223966527563
2017-01-01	17.3967053979831