Year	Percent of Total
1960-01-01	54.7401286206370
1961-01-01	54.4688457609806
1962-01-01	54.1146932770422
1963-01-01	53.7154874055220
1964-01-01	53.3641608049284
1965-01-01	53.1184461478878
1966-01-01	53.0405740785387
1967-01-01	53.0660263775275
1968-01-01	53.1653337424377
1969-01-01	53.2513317191283
1970-01-01	53.2422484247302
1971-01-01	52.5497557336414
1972-01-01	51.7364048250849
1973-01-01	50.8656306976900
1974-01-01	50.0493742352360
1975-01-01	49.3716560262607
1976-01-01	49.2399322169059
1977-01-01	49.2654025017192
1978-01-01	49.3649783837249
1979-01-01	49.4416703679278
1980-01-01	49.4555672637864
1981-01-01	49.3913510204253
1982-01-01	49.3113394700864
1983-01-01	49.2627535389401
1984-01-01	49.3252990951966
1985-01-01	49.5323133961839
1986-01-01	49.8163808376190
1987-01-01	50.1922520506305
1988-01-01	50.6594025033564
1989-01-01	51.1958661579605
1990-01-01	51.7688558234992
1991-01-01	52.1688027859443
1992-01-01	52.6399214433571
1993-01-01	53.1329539027150
1994-01-01	53.5975374042523
1995-01-01	54.0109958939383
1996-01-01	54.2754601874582
1997-01-01	54.5220780793111
1998-01-01	54.7548528963785
1999-01-01	54.9923045888558
2000-01-01	55.2414028777850
2001-01-01	55.3373457307133
2002-01-01	55.4211026921716
2003-01-01	55.4982552504762
2004-01-01	55.5798954451436
2005-01-01	55.6817093544165
2006-01-01	55.7330159402769
2007-01-01	55.7773765569846
2008-01-01	55.8136446260186
2009-01-01	55.8550144454628
2010-01-01	55.9228102086057
2011-01-01	56.0198586396943
2012-01-01	56.2001047991863
2013-01-01	56.4395142614279
2014-01-01	56.7122035641803
2015-01-01	57.0051507961095
2016-01-01	57.3226741227756
2017-01-01	57.6504515468403