Year	Percent of Total
1960-01-01	53.4468090019111
1961-01-01	53.4539777203435
1962-01-01	53.6903116519909
1963-01-01	54.0603839388838
1964-01-01	54.4276445143350
1965-01-01	54.7293325033922
1966-01-01	55.0088074678822
1967-01-01	55.1994739939233
1968-01-01	55.3703333104086
1969-01-01	55.6328596194439
1970-01-01	56.0355656477669
1971-01-01	56.3345466628783
1972-01-01	56.7929381588991
1973-01-01	57.3417379466344
1974-01-01	57.8691682838362
1975-01-01	58.3160168027114
1976-01-01	58.7072178277929
1977-01-01	58.9855010119614
1978-01-01	59.2037390348946
1979-01-01	59.4448550833760
1980-01-01	59.7442074465198
1981-01-01	59.8924364602465
1982-01-01	60.1237863662767
1983-01-01	60.4002708242909
1984-01-01	60.6683404150426
1985-01-01	60.9093155439043
1986-01-01	61.1768585945369
1987-01-01	61.4592611880926
1988-01-01	61.7580516365502
1989-01-01	62.0799670942993
1990-01-01	62.4265502838968
1991-01-01	62.8331961107738
1992-01-01	63.2035027829046
1993-01-01	63.5714068981273
1994-01-01	63.9810108635330
1995-01-01	64.4502823212495
1996-01-01	64.9028582439044
1997-01-01	65.4368128604409
1998-01-01	66.0162801608835
1999-01-01	66.5646442681258
2000-01-01	67.0275878878953
2001-01-01	67.2814924548939
2002-01-01	67.4354094851333
2003-01-01	67.5093143190478
2004-01-01	67.5459766810110
2005-01-01	67.5667792325952
2006-01-01	67.4901275541810
2007-01-01	67.4406910295193
2008-01-01	67.4023274637027
2009-01-01	67.3451610618256
2010-01-01	67.2542261242785
2011-01-01	67.0294935022698
2012-01-01	66.7799225001475
2013-01-01	66.5293417773355
2014-01-01	66.3068808087680
2015-01-01	66.1259561147898
2016-01-01	66.0176035839521
2017-01-01	65.9188231672330