Year	Percent of Total
1960-01-01	42.7319690053861
1961-01-01	43.2678831861578
1962-01-01	43.8207837061155
1963-01-01	44.3107330136545
1964-01-01	44.6297147636270
1965-01-01	44.7422101641287
1966-01-01	44.8778044083792
1967-01-01	44.8084720644359
1968-01-01	44.6005971306935
1969-01-01	44.3477227986083
1970-01-01	44.0994163921525
1971-01-01	43.9524169513424
1972-01-01	43.7825215404862
1973-01-01	43.6114962880050
1974-01-01	43.4568215066618
1975-01-01	43.3343994116323
1976-01-01	43.2829611016354
1977-01-01	43.2665819667118
1978-01-01	43.2889963186478
1979-01-01	43.3682492302093
1980-01-01	43.5278194858724
1981-01-01	43.9305683584679
1982-01-01	44.3546492432837
1983-01-01	44.7737743341221
1984-01-01	45.1381150154939
1985-01-01	45.4040265804854
1986-01-01	45.7824579984239
1987-01-01	45.9700088375440
1988-01-01	45.9643465668172
1989-01-01	45.7678748829301
1990-01-01	45.3744176312158
1991-01-01	44.9868710704539
1992-01-01	44.4731578923700
1993-01-01	43.8224804919268
1994-01-01	43.0351179675220
1995-01-01	42.1237667733256
1996-01-01	40.7862652034230
1997-01-01	39.3902529043076
1998-01-01	37.9548495844251
1999-01-01	36.4768993459536
2000-01-01	34.9406792678155
2001-01-01	33.2153980688148
2002-01-01	31.4064359601096
2003-01-01	29.5397901256996
2004-01-01	27.7142038378502
2005-01-01	26.0511562248804
2006-01-01	25.1825675564119
2007-01-01	24.4838316581103
2008-01-01	23.9819932975446
2009-01-01	23.6545338416326
2010-01-01	23.4588452335495
2011-01-01	23.3776502392015
2012-01-01	23.3745161475381
2013-01-01	23.4364460567536
2014-01-01	23.5336118007386
2015-01-01	23.6321054834253
2016-01-01	23.6737965745489
2017-01-01	23.6886773776179