Year	Percent of Total
1960-01-01	40.8247150833828
1961-01-01	41.1226533961286
1962-01-01	41.4089502892201
1963-01-01	41.6494521017941
1964-01-01	41.7698871606133
1965-01-01	41.7424562951065
1966-01-01	42.0736927591695
1967-01-01	42.2109533859580
1968-01-01	42.2116182177834
1969-01-01	42.1543989741721
1970-01-01	42.0842168785074
1971-01-01	42.3843210307501
1972-01-01	42.5881884837603
1973-01-01	42.7259926853209
1974-01-01	42.8110869569314
1975-01-01	42.8481160480930
1976-01-01	43.2666699308889
1977-01-01	43.5736780326444
1978-01-01	43.7951808551673
1979-01-01	43.9551106944951
1980-01-01	44.0664524156552
1981-01-01	44.4524372285761
1982-01-01	44.7434206465488
1983-01-01	44.9542488390710
1984-01-01	45.0888763446611
1985-01-01	45.1465668116593
1986-01-01	45.6192606462921
1987-01-01	45.9831715329092
1988-01-01	46.2608095514238
1989-01-01	46.4860652183619
1990-01-01	46.6808652093728
1991-01-01	46.7699329928851
1992-01-01	46.8045433474402
1993-01-01	46.7955752321241
1994-01-01	46.7402229246417
1995-01-01	46.6371838054235
1996-01-01	46.7247415746068
1997-01-01	46.7239576772769
1998-01-01	46.6704075346540
1999-01-01	46.6087875688444
2000-01-01	46.5640896123067
2001-01-01	46.6455738459176
2002-01-01	46.7167125085135
2003-01-01	46.7797261303670
2004-01-01	46.8282038291769
2005-01-01	46.8617084322915
2006-01-01	47.0726081010873
2007-01-01	47.2294317341403
2008-01-01	47.3455137479863
2009-01-01	47.4268510317633
2010-01-01	47.4704388068127
2011-01-01	47.7001174120901
2012-01-01	47.8483157333786
2013-01-01	47.9281965609767
2014-01-01	47.9534978976995
2015-01-01	47.9296114788808
2016-01-01	47.8370434808606
2017-01-01	47.7058652851529