Year	Percent of Total
1960-01-01	49.8840655164926
1961-01-01	49.2880114803178
1962-01-01	48.8024181791296
1963-01-01	48.4281840263068
1964-01-01	48.1653736996010
1965-01-01	48.0047614323141
1966-01-01	47.7273247877144
1967-01-01	47.5818958403007
1968-01-01	47.5254957392443
1969-01-01	47.5054556081517
1970-01-01	47.4925909745148
1971-01-01	47.3520769522558
1972-01-01	47.2394288659582
1973-01-01	47.1542999869432
1974-01-01	47.1067070484963
1975-01-01	47.0991676274331
1976-01-01	46.9800890266737
1977-01-01	46.9337932543073
1978-01-01	46.9367951747511
1979-01-01	46.9623667515980
1980-01-01	46.9979820505145
1981-01-01	46.9576362156252
1982-01-01	46.9473040981399
1983-01-01	46.9740897235458
1984-01-01	47.0543102877440
1985-01-01	47.1959076342569
1986-01-01	47.2678923495627
1987-01-01	47.4192585196170
1988-01-01	47.6417147072424
1989-01-01	47.9333603793607
1990-01-01	48.2953984374409
1991-01-01	48.6380005159722
1992-01-01	49.0866851095257
1993-01-01	49.6027314315686
1994-01-01	50.1300111802986
1995-01-01	50.6346526218973
1996-01-01	50.9909074741150
1997-01-01	51.2678509174896
1998-01-01	51.5192592977521
1999-01-01	51.8182100709347
2000-01-01	52.1887915044103
2001-01-01	52.3603465954934
2002-01-01	52.6634168130683
2003-01-01	53.0232119608383
2004-01-01	53.3399680814768
2005-01-01	53.5727272263249
2006-01-01	53.7648713094148
2007-01-01	53.8770730140641
2008-01-01	53.9565508857370
2009-01-01	54.0829601380851
2010-01-01	54.2946613594069
2011-01-01	54.5345606906647
2012-01-01	54.8752000985002
2013-01-01	55.2793884754202
2014-01-01	55.6886076361918
2015-01-01	56.0747391109021
2016-01-01	56.4827092776426
2017-01-01	56.8471739418512