Year	Percent of Total
1960-01-01	43.5825485462506
1961-01-01	43.8711806247636
1962-01-01	44.2351906869791
1963-01-01	44.6003052279955
1964-01-01	44.8556707570829
1965-01-01	44.9643845301110
1966-01-01	45.3116877061511
1967-01-01	45.4698992555093
1968-01-01	45.4879376690359
1969-01-01	45.4236791417300
1970-01-01	45.2876282770663
1971-01-01	45.4396385453149
1972-01-01	45.4808302485830
1973-01-01	45.4215604905980
1974-01-01	45.3005249289432
1975-01-01	45.1651017269809
1976-01-01	44.9496063678533
1977-01-01	44.7409631649165
1978-01-01	44.5529218901069
1979-01-01	44.3831899354897
1980-01-01	44.2427972873217
1981-01-01	44.5537087442091
1982-01-01	44.7919709898910
1983-01-01	45.0215881932993
1984-01-01	45.3025096624762
1985-01-01	45.6438722893298
1986-01-01	46.1064759019036
1987-01-01	46.5653956023334
1988-01-01	46.9777389058629
1989-01-01	47.2797093346545
1990-01-01	47.4460960055693
1991-01-01	48.1707664747761
1992-01-01	48.7044214953916
1993-01-01	49.0748342082802
1994-01-01	49.3202797803055
1995-01-01	49.4549029881964
1996-01-01	49.5831396603804
1997-01-01	49.6313294766101
1998-01-01	49.5972586105673
1999-01-01	49.4858845601328
2000-01-01	49.3154505143651
2001-01-01	48.5531883153145
2002-01-01	47.7821112562966
2003-01-01	47.0345009494309
2004-01-01	46.3484679533491
2005-01-01	45.7498286810604
2006-01-01	45.2931975113018
2007-01-01	44.9020998988233
2008-01-01	44.5756736510176
2009-01-01	44.3058695391736
2010-01-01	44.0879190320899
2011-01-01	44.2364179917793
2012-01-01	44.3586763965831
2013-01-01	44.4744820569101
2014-01-01	44.6054859636123
2015-01-01	44.7526930848973
2016-01-01	44.8739024851206
2017-01-01	44.9945394272681