Year	Percent of Total
1960-01-01	3.69739997698185
1961-01-01	3.71191533497550
1962-01-01	3.71872872353065
1963-01-01	3.71888635506256
1964-01-01	3.71453824294358
1965-01-01	3.70622311848784
1966-01-01	3.71910049143164
1967-01-01	3.72672983900636
1968-01-01	3.72853998523459
1969-01-01	3.72688008249952
1970-01-01	3.72305214777840
1971-01-01	3.73999871623940
1972-01-01	3.75217765365162
1973-01-01	3.75905692711954
1974-01-01	3.75610685022962
1975-01-01	3.74306646570350
1976-01-01	3.74020505991134
1977-01-01	3.72745470336699
1978-01-01	3.70746182687976
1979-01-01	3.68315717704504
1980-01-01	3.65571954772065
1981-01-01	3.64263815790047
1982-01-01	3.62639465613424
1983-01-01	3.61073031963824
1984-01-01	3.59997503269174
1985-01-01	3.59873256724589
1986-01-01	3.61603895507794
1987-01-01	3.63915431177834
1988-01-01	3.66803249412672
1989-01-01	3.70214819179131
1990-01-01	3.73040445068848
1991-01-01	3.79077647874076
1992-01-01	3.86836831367566
1993-01-01	3.92917719770138
1994-01-01	3.99237431431079
1995-01-01	4.04295110048918
1996-01-01	4.10672337486922
1997-01-01	4.16660373012276
1998-01-01	4.22335357921989
1999-01-01	4.27734451061714
2000-01-01	4.32883129298756
2001-01-01	4.38495280211230
2002-01-01	4.43759926312304
2003-01-01	4.48610661322115
2004-01-01	4.52780636695487
2005-01-01	4.56141044205396
2006-01-01	4.56914819595385
2007-01-01	4.56909377469261
2008-01-01	4.56637998753841
2009-01-01	4.56794486001906
2010-01-01	4.57727626701427
2011-01-01	4.59252040401191
2012-01-01	4.61077744069878
2013-01-01	4.63786555778739
2014-01-01	4.68275017906765
2015-01-01	4.75110874430267
2016-01-01	4.85419643994701
2017-01-01	4.98026135641337