Year	Percent of Total
1960-01-01	3.29202491901690
1961-01-01	3.32792616029182
1962-01-01	3.35899434156012
1963-01-01	3.38591541955502
1964-01-01	3.41009358962592
1965-01-01	3.43257339634377
1966-01-01	3.45984052591428
1967-01-01	3.48597767984708
1968-01-01	3.51095138107645
1969-01-01	3.53373529727930
1970-01-01	3.55442814497041
1971-01-01	3.58950552645074
1972-01-01	3.61862304797348
1973-01-01	3.64429385369122
1974-01-01	3.66988933409321
1975-01-01	3.69705172350825
1976-01-01	3.73594749939918
1977-01-01	3.77420498287205
1978-01-01	3.80966325119682
1979-01-01	3.83852587412238
1980-01-01	3.85967363430724
1981-01-01	3.88854745029565
1982-01-01	3.90891783919044
1983-01-01	3.92589957272642
1984-01-01	3.94583531537263
1985-01-01	3.97230213088648
1986-01-01	4.01602685108269
1987-01-01	4.06262545296558
1988-01-01	4.11236826972491
1989-01-01	4.16502577217576
1990-01-01	4.22072766711455
1991-01-01	4.29613642481437
1992-01-01	4.37128889321507
1993-01-01	4.44507837806986
1994-01-01	4.51576169271673
1995-01-01	4.58300161122715
1996-01-01	4.67690138000885
1997-01-01	4.76595390935478
1998-01-01	4.85358814076644
1999-01-01	4.94395606971725
2000-01-01	5.03972161736684
2001-01-01	5.15153033420080
2002-01-01	5.26800055965717
2003-01-01	5.38785588553571
2004-01-01	5.50851615279741
2005-01-01	5.62940778056446
2006-01-01	5.75224824170103
2007-01-01	5.87506951831412
2008-01-01	6.00102570544465
2009-01-01	6.13379188363936
2010-01-01	6.27620400446364
2011-01-01	6.42930411573022
2012-01-01	6.58721505992455
2013-01-01	6.75551214913665
2014-01-01	6.94130315743166
2015-01-01	7.14899129486824
2016-01-01	7.36870910355157
2017-01-01	7.60742951295305