Year	Percent of Total
1960-01-01	7.67989549280927
1961-01-01	7.68224579167825
1962-01-01	7.68413188022482
1963-01-01	7.68950690854938
1964-01-01	7.70268242457771
1965-01-01	7.72763419271217
1966-01-01	7.75121235031389
1967-01-01	7.79270432813318
1968-01-01	7.85113351294876
1969-01-01	7.92099223636554
1970-01-01	7.99862507054461
1971-01-01	8.09194749890491
1972-01-01	8.17406570655051
1973-01-01	8.25789420662613
1974-01-01	8.35937961808707
1975-01-01	8.48537858679717
1976-01-01	8.65706901713883
1977-01-01	8.84692258803739
1978-01-01	9.04505947801794
1979-01-01	9.23558637150674
1980-01-01	9.41247210077734
1981-01-01	9.58261740212904
1982-01-01	9.73679191378857
1983-01-01	9.88891497910411
1984-01-01	10.05792229550250
1985-01-01	10.25289954772660
1986-01-01	10.43410658087120
1987-01-01	10.63292013937950
1988-01-01	10.84290163197480
1989-01-01	11.05175164346140
1990-01-01	11.25228399707070
1991-01-01	11.41729001291730
1992-01-01	11.56270620958380
1993-01-01	11.69565867491280
1994-01-01	11.82540056586140
1995-01-01	11.95861667306450
1996-01-01	12.08135187568540
1997-01-01	12.20833256697040
1998-01-01	12.33638567580090
1999-01-01	12.45775415707240
2000-01-01	12.57037524320600
2001-01-01	12.67791128703380
2002-01-01	12.77197783243000
2003-01-01	12.86633034235760
2004-01-01	12.97861554093460
2005-01-01	13.12037172966530
2006-01-01	13.27594387254130
2007-01-01	13.44890716310380
2008-01-01	13.64997963750330
2009-01-01	13.89278330513110
2010-01-01	14.18638268252070
2011-01-01	14.49750948373100
2012-01-01	14.86380002925440
2013-01-01	15.27452954496880
2014-01-01	15.70742234008920
2015-01-01	16.14769955439700
2016-01-01	16.57274042292080
2017-01-01	16.98434960993960