Year	Percent of Total
1960-01-01	2.76266537673588
1961-01-01	2.74493243243243
1962-01-01	2.72725726280837
1963-01-01	2.70634029781081
1964-01-01	2.67881076381600
1965-01-01	2.64400674813850
1966-01-01	2.64108630307385
1967-01-01	2.63134002785801
1968-01-01	2.61654616604355
1969-01-01	2.59887108119000
1970-01-01	2.57975426601570
1971-01-01	2.58242133162547
1972-01-01	2.58254187884550
1973-01-01	2.57973905432637
1974-01-01	2.57422203209658
1975-01-01	2.56690262119063
1976-01-01	2.58252828506793
1977-01-01	2.59394601535383
1978-01-01	2.60134400851649
1979-01-01	2.60582834985627
1980-01-01	2.60750186540574
1981-01-01	2.62697136916513
1982-01-01	2.64096002369412
1983-01-01	2.65131368798611
1984-01-01	2.65924886951261
1985-01-01	2.66625404854292
1986-01-01	2.69407858909997
1987-01-01	2.71735692285702
1988-01-01	2.73759538525147
1989-01-01	2.75700890463514
1990-01-01	2.77771799861948
1991-01-01	2.85166391295742
1992-01-01	2.92315545975703
1993-01-01	2.99150029025052
1994-01-01	3.05372680681510
1995-01-01	3.10760708429566
1996-01-01	3.17201470039427
1997-01-01	3.22820946747434
1998-01-01	3.27678947765090
1999-01-01	3.31823964354141
2000-01-01	3.35242178954793
2001-01-01	3.38215059002769
2002-01-01	3.40103119564637
2003-01-01	3.41238515728553
2004-01-01	3.41963959681990
2005-01-01	3.42496246542271
2006-01-01	3.46909789094114
2007-01-01	3.50494494540769
2008-01-01	3.53288116436188
2009-01-01	3.55348332635012
2010-01-01	3.56715343761103
2011-01-01	3.60740073614038