Year	Percent of Total
1960-01-01	56.4480046241810
1961-01-01	56.1660786444339
1962-01-01	55.9138817190323
1963-01-01	55.6927916654288
1964-01-01	55.5151004655071
1965-01-01	55.3828822357998
1966-01-01	55.0098112921743
1967-01-01	54.7325188465404
1968-01-01	54.5189474318338
1969-01-01	54.3335927381729
1970-01-01	54.1597684306797
1971-01-01	53.7887901077153
1972-01-01	53.4725539283934
1973-01-01	53.2023256370596
1974-01-01	52.9770480757514
1975-01-01	52.7937224986530
1976-01-01	52.4581244144785
1977-01-01	52.1946797661985
1978-01-01	51.9853114713410
1979-01-01	51.8099281097595
1980-01-01	51.6562907487903
1981-01-01	51.3668555814827
1982-01-01	51.1218131746826
1983-01-01	50.9198144246222
1984-01-01	50.7647145226935
1985-01-01	50.6568492430316
1986-01-01	50.4068555115111
1987-01-01	50.2470486451637
1988-01-01	50.1575941660381
1989-01-01	50.1216303674940
1990-01-01	50.1355757955166
1991-01-01	50.0527372764946
1992-01-01	50.0416272763544
1993-01-01	50.1016977899551
1994-01-01	50.2380992336949
1995-01-01	50.4512891098532
1996-01-01	50.5655902868075
1997-01-01	50.7662496206432
1998-01-01	51.0352137938537
1999-01-01	51.3438689552590
2000-01-01	51.6682276832999
2001-01-01	51.8480656526795
2002-01-01	52.0455849049847
2003-01-01	52.2551169559657
2004-01-01	52.4758269625577
2005-01-01	52.7037256336464
2006-01-01	52.7812803464129
2007-01-01	52.8996315326629
2008-01-01	53.0389155174631
2009-01-01	53.1803998252210
2010-01-01	53.3185231512789
2011-01-01	53.3548221439816
2012-01-01	53.4176331015331
2013-01-01	53.5079492872898
2014-01-01	53.6342602917710
2015-01-01	53.8015115884624
2016-01-01	53.9314436177805
2017-01-01	54.1098807681654