Year	Percent of Total
1960-01-01	3.88575941873093
1961-01-01	3.82037967492862
1962-01-01	3.73597590425151
1963-01-01	3.63744741536526
1964-01-01	3.52830782606089
1965-01-01	3.41220765404377
1966-01-01	3.34188435551036
1967-01-01	3.26258717308264
1968-01-01	3.17977205737465
1969-01-01	3.09944427537090
1970-01-01	3.02513304267208
1971-01-01	2.98575587057581
1972-01-01	2.95107605188422
1973-01-01	2.91901076003135
1974-01-01	2.88708054908218
1975-01-01	2.85550211160926
1976-01-01	2.84071273200382
1977-01-01	2.82499144169342
1978-01-01	2.81001633718719
1979-01-01	2.79733874032891
1980-01-01	2.78822637046019
1981-01-01	2.78871288175660
1982-01-01	2.79029689804836
1983-01-01	2.79600817663705
1984-01-01	2.80942105284229
1985-01-01	2.83206510641670
1986-01-01	2.88592749545573
1987-01-01	2.94091811500734
1988-01-01	2.99683585843867
1989-01-01	3.05372201896365
1990-01-01	3.11164184056433
1991-01-01	3.17560949525042
1992-01-01	3.24160116826388
1993-01-01	3.30884200728915
1994-01-01	3.37542530869703
1995-01-01	3.44085573911079
1996-01-01	3.51900480630610
1997-01-01	3.58902375466289
1998-01-01	3.65223610730975
1999-01-01	3.71107225923810
2000-01-01	3.76628786513787
2001-01-01	3.82346248533700
2002-01-01	3.87458016848439
2003-01-01	3.91978065339590
2004-01-01	3.95829166490644
2005-01-01	3.98909798007419
2006-01-01	4.05028704729373
2007-01-01	4.10542945302144
2008-01-01	4.15081385040801
2009-01-01	4.18104532014345
2010-01-01	4.19380983410978
2011-01-01	4.23150008371679
2012-01-01	4.25448569581970
2013-01-01	4.27090512058645
2014-01-01	4.29152748469240
2015-01-01	4.32301436016780
2016-01-01	4.36464257832952
2017-01-01	4.42360763377747