Year	Percent of Total
1960-01-01	54.4772290170385
1961-01-01	54.1665842924275
1962-01-01	53.8671804708938
1963-01-01	53.6066440272506
1964-01-01	53.4309947569065
1965-01-01	53.3523098528794
1966-01-01	53.0780882857666
1967-01-01	52.9248397986513
1968-01-01	52.8560418721889
1969-01-01	52.8276484253255
1970-01-01	52.8184183082626
1971-01-01	52.6067591776452
1972-01-01	52.4654664058294
1973-01-01	52.3757289258998
1974-01-01	52.3220780919036
1975-01-01	52.2939834781992
1976-01-01	52.1361803821522
1977-01-01	52.0258117645535
1978-01-01	51.9594620052028
1979-01-01	51.9441434502281
1980-01-01	51.9865542958905
1981-01-01	51.8693732849364
1982-01-01	51.8197964608462
1983-01-01	51.8296680560255
1984-01-01	51.8882620498184
1985-01-01	51.9875116232027
1986-01-01	51.9202198948193
1987-01-01	51.9281449992447
1988-01-01	51.9934981360305
1989-01-01	52.0937694820752
1990-01-01	52.1883038366494
1991-01-01	52.3128060898012
1992-01-01	52.4614381678864
1993-01-01	52.6323971614804
1994-01-01	52.8323233797829
1995-01-01	53.0667579050851
1996-01-01	53.1641450172759
1997-01-01	53.3061101734056
1998-01-01	53.4844766179294
1999-01-01	53.6823181334541
2000-01-01	53.8852558844338
2001-01-01	53.9704315254925
2002-01-01	54.0845945122773
2003-01-01	54.2166665208718
2004-01-01	54.3590316362506
2005-01-01	54.5091084880285
2006-01-01	54.5567247762205
2007-01-01	54.6212802762909
2008-01-01	54.7043870036917
2009-01-01	54.8098618473708
2010-01-01	54.9384365131818
2011-01-01	54.9961271036236
2012-01-01	55.0921184223863
2013-01-01	55.2200608648160
2014-01-01	55.3706349582786
2015-01-01	55.5381588291611
2016-01-01	55.7056760489629
2017-01-01	55.8937287894993