Year	Percent of Total
1960-01-01	44.6148073570676
1961-01-01	44.9565850449661
1962-01-01	45.1994887667267
1963-01-01	45.3720876566213
1964-01-01	45.4999081709204
1965-01-01	45.5912983805387
1966-01-01	45.8050929559382
1967-01-01	45.9590833670694
1968-01-01	46.0516637857921
1969-01-01	46.0738957579755
1970-01-01	46.0257914471829
1971-01-01	46.1143882179696
1972-01-01	46.1159448610401
1973-01-01	46.0501613399751
1974-01-01	45.9388436538864
1975-01-01	45.7956206357258
1976-01-01	45.7951114500758
1977-01-01	45.7337314094566
1978-01-01	45.6282526957072
1979-01-01	45.4959502966249
1980-01-01	45.3461835556700
1981-01-01	45.3290756191820
1982-01-01	45.2789448682070
1983-01-01	45.2016626646641
1984-01-01	45.0994065592290
1985-01-01	44.9740725967292
1986-01-01	44.9916316566243
1987-01-01	44.9738051436201
1988-01-01	44.9252262868161
1989-01-01	44.8503818261869
1990-01-01	44.7515934861635
1991-01-01	44.7231491241616
1992-01-01	44.6555480061360
1993-01-01	44.5565055953043
1994-01-01	44.4368385466898
1995-01-01	44.3039437920995
1996-01-01	44.1018752776625
1997-01-01	43.8821766322841
1998-01-01	43.6489079221394
1999-01-01	43.4007797465234
2000-01-01	43.1372512834217
2001-01-01	42.9640427286204
2002-01-01	42.7636442356819
2003-01-01	42.5446473710712
2004-01-01	42.3178738953925
2005-01-01	42.0894874022589
2006-01-01	41.9269632586932
2007-01-01	41.7510976811721
2008-01-01	41.5661322930524
2009-01-01	41.3771201909256
2010-01-01	41.1885382720195
2011-01-01	41.0191915801071
2012-01-01	40.8412634302977
2013-01-01	40.6556990702377
2014-01-01	40.4567019035808
2015-01-01	40.2390909779953
2016-01-01	40.1045752424194
2017-01-01	39.9277722375358