Year	Percent of Total
1960-01-01	55.2146121362874
1961-01-01	54.8808348001289
1962-01-01	54.5730445704994
1963-01-01	54.2916107636831
1964-01-01	54.0490727274620
1965-01-01	53.8489727403835
1966-01-01	53.5152633788158
1967-01-01	53.2550453262475
1968-01-01	53.0481951292256
1969-01-01	52.8719455275528
1970-01-01	52.7134140086693
1971-01-01	52.4772810158654
1972-01-01	52.2839427018486
1973-01-01	52.1295788167083
1974-01-01	52.0155053834536
1975-01-01	51.9410530181964
1976-01-01	51.7007633364083
1977-01-01	51.5234885480432
1978-01-01	51.4035777913587
1979-01-01	51.3363612811386
1980-01-01	51.3193672602565
1981-01-01	51.2531430175924
1982-01-01	51.2679665538298
1983-01-01	51.3469525897574
1984-01-01	51.4745673873815
1985-01-01	51.6432697143018
1986-01-01	51.7509229696268
1987-01-01	51.9018329623777
1988-01-01	52.0947516341114
1989-01-01	52.3315710936552
1990-01-01	52.6076058705398
1991-01-01	52.8406489904186
1992-01-01	53.1176720533481
1993-01-01	53.4185486389124
1994-01-01	53.7177084125345
1995-01-01	53.9984388703423
1996-01-01	54.1923130623481
1997-01-01	54.3750316458901
1998-01-01	54.5455678667180
1999-01-01	54.7115367446938
2000-01-01	54.8763736050819
2001-01-01	54.8737169786170
2002-01-01	54.9094265639033
2003-01-01	54.9587311303665
2004-01-01	54.9911397752118
2005-01-01	54.9912418311552
2006-01-01	54.9937343276862
2007-01-01	54.9787412549425
2008-01-01	54.9567907159268
2009-01-01	54.9564709599522
2010-01-01	54.9952777639101
2011-01-01	54.7091006995765
2012-01-01	54.4980179623310
2013-01-01	54.3511765917911
2014-01-01	54.2550236589223
2015-01-01	54.2062811471104
2016-01-01	54.2339851508666
2017-01-01	54.3221593879200