Year	Percent of Total
1960-01-01	5.90333897683836
1961-01-01	6.10570875875051
1962-01-01	6.31012080852913
1963-01-01	6.43937755336876
1964-01-01	6.47636560340254
1965-01-01	6.47938089320201
1966-01-01	7.10566060945690
1967-01-01	7.81589290183796
1968-01-01	8.56417702462686
1969-01-01	9.31872439627594
1970-01-01	10.07511151019930
1971-01-01	10.04092716703790
1972-01-01	9.98707010487228
1973-01-01	9.91133833298431
1974-01-01	9.81989261122242
1975-01-01	9.72428069041408
1976-01-01	9.67676196211907
1977-01-01	9.61086535803152
1978-01-01	9.53136348850577
1979-01-01	9.44293548192603
1980-01-01	9.35051633630286
1981-01-01	9.46206540302653
1982-01-01	9.57334227745474
1983-01-01	9.67875322190477
1984-01-01	9.76943373889413
1985-01-01	9.84315469804046
1986-01-01	9.83770413327325
1987-01-01	9.83977992203268
1988-01-01	9.85377722922174
1989-01-01	9.87678484882377
1990-01-01	9.90655010213745
1991-01-01	9.92671705427841
1992-01-01	9.94792714046432
1993-01-01	9.98313284502859
1994-01-01	10.03942134247590
1995-01-01	10.11627526350740
1996-01-01	10.11285482521070
1997-01-01	10.12340775051840
1998-01-01	10.14796897559600
1999-01-01	10.18357540089630
2000-01-01	10.22892314738050
2001-01-01	10.28114657985880
2002-01-01	10.35624576494990
2003-01-01	10.46596944531950
2004-01-01	10.60777308221420
2005-01-01	10.76564382313960
2006-01-01	10.88149408565590
2007-01-01	10.98981679251530
2008-01-01	11.10540948608630
2009-01-01	11.24494115161430
2010-01-01	11.41723897117310
2011-01-01	11.66686669600430
2012-01-01	11.93970021020880
2013-01-01	12.23205606104050
2014-01-01	12.53300980900090
2015-01-01	12.83281007075890
2016-01-01	13.12423886336930
2017-01-01	13.41646100931630