Year	Percent of Total
1960-01-01	4.28824098690724
1961-01-01	4.36126449171745
1962-01-01	4.43182311802267
1963-01-01	4.47328129851497
1964-01-01	4.47718691332504
1965-01-01	4.46719694295030
1966-01-01	4.54122863477079
1967-01-01	4.59774734494157
1968-01-01	4.62645410608921
1969-01-01	4.62778226552083
1970-01-01	4.62173579109063
1971-01-01	4.68260745801309
1972-01-01	4.73439481471044
1973-01-01	4.78849124374221
1974-01-01	4.83359746434231
1975-01-01	4.88662555001867
1976-01-01	4.93759441766779
1977-01-01	4.98710460777623
1978-01-01	5.01807134251742
1979-01-01	5.04772551380170
1980-01-01	5.08445845728767
1981-01-01	5.17918959145107
1982-01-01	5.27015203790217
1983-01-01	5.35277823040574
1984-01-01	5.41665327634412
1985-01-01	5.46757581989906
1986-01-01	5.86927281350345
1987-01-01	6.27470732786910
1988-01-01	6.67250791939072
1989-01-01	7.06919885845420
1990-01-01	7.46752541882259
1991-01-01	7.52875367447701
1992-01-01	7.56596794081381
1993-01-01	7.59237975829763
1994-01-01	7.62769626911399
1995-01-01	7.67253339136585
1996-01-01	7.63939223108104
1997-01-01	7.61553022781727
1998-01-01	7.59940724492927
1999-01-01	7.58899801510582
2000-01-01	7.56870066072418
2001-01-01	7.52536853796446
2002-01-01	7.47982949744309
2003-01-01	7.43602964472303
2004-01-01	7.38177268553044
2005-01-01	7.32619079614450
2006-01-01	7.53414305319605
2007-01-01	7.76684520109034
2008-01-01	8.03037466020565
2009-01-01	8.34161686800529
2010-01-01	8.71190172673543
2011-01-01	8.83094021814165
2012-01-01	8.95987645494323
2013-01-01	9.09939656153934
2014-01-01	9.24209702926522
2015-01-01	9.39471575454556
2016-01-01	9.55200404460298
2017-01-01	9.72132137505312