Year	Percent of Total
1960-01-01	3.34695549855423
1961-01-01	3.33672148675455
1962-01-01	3.32010750525043
1963-01-01	3.29965943684230
1964-01-01	3.27762085077970
1965-01-01	3.25554909638093
1966-01-01	3.25400079199833
1967-01-01	3.25067138024311
1968-01-01	3.24526661264694
1969-01-01	3.23673337891968
1970-01-01	3.22499485497854
1971-01-01	3.24495653046904
1972-01-01	3.26064862370664
1973-01-01	3.27262328011130
1974-01-01	3.28210211231037
1975-01-01	3.28991386429256
1976-01-01	3.33372251410780
1977-01-01	3.37478556403702
1978-01-01	3.41463392549116
1979-01-01	3.45521176473725
1980-01-01	3.49852337108008
1981-01-01	3.56723985492864
1982-01-01	3.63766791092151
1983-01-01	3.71069475013369
1984-01-01	3.78649353343767
1985-01-01	3.86558513036520
1986-01-01	3.96230223516284
1987-01-01	4.06101334582843
1988-01-01	4.16043258153148
1989-01-01	4.25843477261513
1990-01-01	4.35375255186315
1991-01-01	4.44259880071122
1992-01-01	4.52614848978702
1993-01-01	4.60966386554622
1994-01-01	4.70078603124107
1995-01-01	4.80410756150961
1996-01-01	4.92839732542303
1997-01-01	5.06116270685460
1998-01-01	5.20081831468845
1999-01-01	5.34551079647743
2000-01-01	5.49518663936658
2001-01-01	5.66617258966448
2002-01-01	5.83911292067088
2003-01-01	6.01180433506628
2004-01-01	6.18011840137316
2005-01-01	6.34139116176071
2006-01-01	6.52839818785770
2007-01-01	6.70179461574183
2008-01-01	6.86496459012412
2009-01-01	7.02259438878095
2010-01-01	7.17709395509152
2011-01-01	7.32353017168990
2012-01-01	7.46983803566038
2013-01-01	7.61806092266609
2014-01-01	7.77093317841574
2015-01-01	7.93114843330939
2016-01-01	8.09890488503673
2017-01-01	8.27312890403714