Year	Percent of Total
1960-01-01	3.51082633700783
1961-01-01	3.54335717090491
1962-01-01	3.56952816853380
1963-01-01	3.58931419079704
1964-01-01	3.60245886324069
1965-01-01	3.60901665465693
1966-01-01	3.62798451529051
1967-01-01	3.63943924739446
1968-01-01	3.64545641856579
1969-01-01	3.64825336632617
1970-01-01	3.64943818616414
1971-01-01	3.66464794894171
1972-01-01	3.67670610305032
1973-01-01	3.68363553139414
1974-01-01	3.68248374224463
1975-01-01	3.67239625416894
1976-01-01	3.66760392512121
1977-01-01	3.65417131926191
1978-01-01	3.63540251167062
1979-01-01	3.61519424775055
1980-01-01	3.59614662342192
1981-01-01	3.58843614469171
1982-01-01	3.57929400724859
1983-01-01	3.56985328826862
1984-01-01	3.56110925750973
1985-01-01	3.55436257895020
1986-01-01	3.56062025789085
1987-01-01	3.56812728039213
1988-01-01	3.57895667234735
1989-01-01	3.59538097144593
1990-01-01	3.60553400951939
1991-01-01	3.64624719769924
1992-01-01	3.70777505833154
1993-01-01	3.75144872435684
1994-01-01	3.79649373903254
1995-01-01	3.82731849370130
1996-01-01	3.87555895490730
1997-01-01	3.91970247507797
1998-01-01	3.96067098152825
1999-01-01	3.99816635619408
2000-01-01	4.03231162714566
2001-01-01	4.06206440623912
2002-01-01	4.08690285357526
2003-01-01	4.10678021275971
2004-01-01	4.12073064680733
2005-01-01	4.12920588724877
2006-01-01	4.13713885291051
2007-01-01	4.13957968403983
2008-01-01	4.14069243063845
2009-01-01	4.14495735718707
2010-01-01	4.15572686307613
2011-01-01	4.17772133721944
2012-01-01	4.20084483365478
2013-01-01	4.22911244049752
2014-01-01	4.26892498033916
2015-01-01	4.32449618113691
2016-01-01	4.39877240792997
2017-01-01	4.48851027094983