Year	Percent of Total
1960-01-01	52.5238741271457
1961-01-01	52.3412751117147
1962-01-01	52.1961155149026
1963-01-01	52.0860526483606
1964-01-01	52.0120256120150
1965-01-01	51.9785094772201
1966-01-01	51.9104685759534
1967-01-01	51.8989466917396
1968-01-01	51.9377802499134
1969-01-01	52.0191618031818
1970-01-01	52.1397039029184
1971-01-01	52.2588549147056
1972-01-01	52.4162320239527
1973-01-01	52.6138117750669
1974-01-01	52.8598745345365
1975-01-01	53.1565059692128
1976-01-01	53.4283623405136
1977-01-01	53.7643710994673
1978-01-01	54.1454963213347
1979-01-01	54.5479962866103
1980-01-01	54.9599257648675
1981-01-01	55.3818855762278
1982-01-01	55.8053546939885
1983-01-01	56.2351226873157
1984-01-01	56.6794092726302
1985-01-01	57.1384541625287
1986-01-01	57.5874976967910
1987-01-01	58.0404359686188
1988-01-01	58.4921671624551
1989-01-01	58.9366523785375
1990-01-01	59.3692293310142
1991-01-01	59.7641231445544
1992-01-01	60.1666215065267
1993-01-01	60.5611253842725
1994-01-01	60.9269934277954
1995-01-01	61.2532986827169
1996-01-01	61.5576981944997
1997-01-01	61.8138216592424
1998-01-01	62.0393376020833
1999-01-01	62.2626167164278
2000-01-01	62.4972321651613
2001-01-01	62.6730435863344
2002-01-01	62.8853081592054
2003-01-01	63.1106945276261
2004-01-01	63.3157375913010
2005-01-01	63.4853391343251
2006-01-01	63.6474193705307
2007-01-01	63.7709634614789
2008-01-01	63.8732599449189
2009-01-01	63.9790634424629
2010-01-01	64.0966155781888
2011-01-01	64.1830614636999
2012-01-01	64.2851539039338
2013-01-01	64.3937597923335
2014-01-01	64.4956206297871
2015-01-01	64.5841064644722
2016-01-01	64.6335420447438
2017-01-01	64.6938566876829