Year	Percent of Total
1960-01-01	54.0737629964080
1961-01-01	53.8132886303812
1962-01-01	53.6172144260712
1963-01-01	53.4775951854287
1964-01-01	53.3954697638547
1965-01-01	53.3687296468112
1966-01-01	53.1272758825917
1967-01-01	52.9828075512682
1968-01-01	52.9088531933053
1969-01-01	52.8760048564641
1970-01-01	52.8670558508050
1971-01-01	52.6581382989302
1972-01-01	52.5042768772313
1973-01-01	52.3973014514066
1974-01-01	52.3344287728563
1975-01-01	52.3108092331666
1976-01-01	52.1233673826119
1977-01-01	52.0046288169491
1978-01-01	51.9330601979587
1979-01-01	51.8904513457313
1980-01-01	51.8694837219492
1981-01-01	51.6664225754955
1982-01-01	51.5303403949219
1983-01-01	51.4528581764177
1984-01-01	51.4297612889171
1985-01-01	51.4572589556683
1986-01-01	51.3454290331274
1987-01-01	51.3087721454446
1988-01-01	51.3355426329770
1989-01-01	51.4168851144288
1990-01-01	51.5476373667743
1991-01-01	51.5777253637286
1992-01-01	51.6736348198775
1993-01-01	51.8210316900558
1994-01-01	52.0043939802697
1995-01-01	52.2122552550186
1996-01-01	52.2446562667193
1997-01-01	52.3187499195912
1998-01-01	52.4243616732440
1999-01-01	52.5549316823869
2000-01-01	52.7049184569166
2001-01-01	52.7062668340474
2002-01-01	52.7529276190545
2003-01-01	52.8283453437128
2004-01-01	52.9158665419498
2005-01-01	53.0080827291454
2006-01-01	53.0035476260425
2007-01-01	53.0256712935026
2008-01-01	53.0738963941607
2009-01-01	53.1510230696939
2010-01-01	53.2568589640300
2011-01-01	53.3210785101354
2012-01-01	53.4238069431534
2013-01-01	53.5589756273440
2014-01-01	53.7212788578001
2015-01-01	53.9072123871382
2016-01-01	54.0501436185901
2017-01-01	54.2298671605870