Year	Percent of Total
1960-01-01	6.08878640012441
1961-01-01	6.17359536619653
1962-01-01	6.25883870516411
1963-01-01	6.35005382932871
1964-01-01	6.45181051474940
1965-01-01	6.56736574454973
1966-01-01	6.70485437452627
1967-01-01	6.84964318330216
1968-01-01	7.00122880389778
1969-01-01	7.15746738886428
1970-01-01	7.31751087349447
1971-01-01	7.50979085788378
1972-01-01	7.68299911643960
1973-01-01	7.84824492091977
1974-01-01	8.02210754492771
1975-01-01	8.21110484799599
1976-01-01	8.41170563821669
1977-01-01	8.62901134888445
1978-01-01	8.82573420469700
1979-01-01	8.94814621797128
1980-01-01	8.97298873385922
1981-01-01	8.93278441748313
1982-01-01	8.80621942082331
1983-01-01	8.63941740900227
1984-01-01	8.49391445110381
1985-01-01	8.40273050236494
1986-01-01	8.39833865291496
1987-01-01	8.42326078109513
1988-01-01	8.48833367600380
1989-01-01	8.60521298340816
1990-01-01	8.78106755624840
1991-01-01	9.03011560523306
1992-01-01	9.33480644854642
1993-01-01	9.65138107887656
1994-01-01	9.91514413388822
1995-01-01	10.09369244295460
1996-01-01	10.26024057264980
1997-01-01	10.32446475336350
1998-01-01	10.34272996184260
1999-01-01	10.39149182163810
2000-01-01	10.50477573700800
2001-01-01	10.73736124508290
2002-01-01	11.02224756764680
2003-01-01	11.30333164130740
2004-01-01	11.48473833378550
2005-01-01	11.51951812230580
2006-01-01	11.53637931903560
2007-01-01	11.44527194042990
2008-01-01	11.30055778327760
2009-01-01	11.17253266316840
2010-01-01	11.09203175884760
2011-01-01	11.09434440530450
2012-01-01	11.11752757679040
2013-01-01	11.15745411707820
2014-01-01	11.22392049270660
2015-01-01	11.33355753222630
2016-01-01	11.53785720872200
2017-01-01	11.78970097547240