Year	Percent of Total
1960-01-01	50.5745752728723
1961-01-01	50.3414082858737
1962-01-01	50.1325193219024
1963-01-01	49.9604479426162
1964-01-01	49.8633580880651
1965-01-01	49.8597574716385
1966-01-01	49.5836393348359
1967-01-01	49.4503299033997
1968-01-01	49.4279324865816
1969-01-01	49.4825295878158
1970-01-01	49.5985459637436
1971-01-01	49.4850068857649
1972-01-01	49.4530290821585
1973-01-01	49.4893723100298
1974-01-01	49.5815227224393
1975-01-01	49.7264413302626
1976-01-01	49.7645137188613
1977-01-01	49.7962181572089
1978-01-01	49.8280805080361
1979-01-01	49.8724930420283
1980-01-01	49.9462839945339
1981-01-01	49.6061489881742
1982-01-01	49.4349331424243
1983-01-01	49.3738183192560
1984-01-01	49.3729785260993
1985-01-01	49.4182052528895
1986-01-01	49.3494918462713
1987-01-01	49.2985429075410
1988-01-01	49.2566761354029
1989-01-01	49.2259680949724
1990-01-01	49.2236792825933
1991-01-01	49.1161100914592
1992-01-01	49.1278944640013
1993-01-01	49.2163622720716
1994-01-01	49.3454430583485
1995-01-01	49.4961926525110
1996-01-01	49.4708330906305
1997-01-01	49.4637605806095
1998-01-01	49.4507627445295
1999-01-01	49.4208669134310
2000-01-01	49.3836900695527
2001-01-01	49.0980783515019
2002-01-01	48.8891448649607
2003-01-01	48.7213505392723
2004-01-01	48.5675872011087
2005-01-01	48.4236273895801
2006-01-01	48.1712862324994
2007-01-01	47.9634434385136
2008-01-01	47.7920218799917
2009-01-01	47.6585776082112
2010-01-01	47.5671480175614
2011-01-01	47.4133758258893
2012-01-01	47.3175004627323
2013-01-01	47.2647952619213
2014-01-01	47.2444408537421
2015-01-01	47.2554884626877
2016-01-01	47.2190932060277
2017-01-01	47.2483101731182