Year	Percent of Total
1960-01-01	2.52467072209591
1961-01-01	2.54543875675441
1962-01-01	2.55052996980535
1963-01-01	2.54370044570064
1964-01-01	2.53115216210543
1965-01-01	2.51643795604185
1966-01-01	2.54084959131425
1967-01-01	2.55933858673353
1968-01-01	2.57073493045814
1969-01-01	2.57178758410881
1970-01-01	2.56069896014896
1971-01-01	2.59052258632238
1972-01-01	2.60531561534609
1973-01-01	2.60837338707999
1974-01-01	2.60817874548027
1975-01-01	2.61183876357527
1976-01-01	2.65881908280745
1977-01-01	2.70552476488610
1978-01-01	2.74331377202085
1979-01-01	2.75097640264251
1980-01-01	2.70992379530094
1981-01-01	2.78655337806728
1982-01-01	2.81668336440882
1983-01-01	2.81590896281875
1984-01-01	2.81107260134577
1985-01-01	2.81538466724526
1986-01-01	2.81648041155043
1987-01-01	2.84100718432579
1988-01-01	2.87448193565935
1989-01-01	2.89670384405751
1990-01-01	2.90071413749749
1991-01-01	2.94096808261376
1992-01-01	2.96493147017348
1993-01-01	2.98069625888130
1994-01-01	3.00113151474071
1995-01-01	3.03216071100378
1996-01-01	3.03680974052285
1997-01-01	3.04578306426768
1998-01-01	3.05924284035017
1999-01-01	3.07187126902911
2000-01-01	3.08003700353034
2001-01-01	3.15377425131262
2002-01-01	3.21814579481681
2003-01-01	3.27616072170470
2004-01-01	3.33162703640873
2005-01-01	3.38685148778078
2006-01-01	3.45865435045440
2007-01-01	3.52824326757938
2008-01-01	3.59674130105747
2009-01-01	3.66469394915959
2010-01-01	3.73340350023832
2011-01-01	3.79676935147242
2012-01-01	3.86118409681728
2013-01-01	3.93156566080167
2014-01-01	4.01595464281809
2015-01-01	4.11931328453079
2016-01-01	4.25869967523919
2017-01-01	4.41230579256104