Year	Percent of Total
1960-01-01	2.54243084841141
1961-01-01	2.57438522766462
1962-01-01	2.58526121702451
1963-01-01	2.57970305415158
1964-01-01	2.56523495151495
1965-01-01	2.54492004979931
1966-01-01	2.56419806110207
1967-01-01	2.57739873530689
1968-01-01	2.58343653253147
1969-01-01	2.57894762196671
1970-01-01	2.56214932424844
1971-01-01	2.58347120632965
1972-01-01	2.59539546661698
1973-01-01	2.59861279809177
1974-01-01	2.59458429629487
1975-01-01	2.58437413236014
1976-01-01	2.59927955927587
1977-01-01	2.60842839763138
1978-01-01	2.61202435917135
1979-01-01	2.61002663767177
1980-01-01	2.60261593074950
1981-01-01	2.60912777717622
1982-01-01	2.61225135554044
1983-01-01	2.61165363514823
1984-01-01	2.60698288980173
1985-01-01	2.59917907762077
1986-01-01	2.60450541464148
1987-01-01	2.60007159750507
1988-01-01	2.58834313244574
1989-01-01	2.57154735294473
1990-01-01	2.55014176217919
1991-01-01	2.54483908243203
1992-01-01	2.53663054152245
1993-01-01	2.52476660608156
1994-01-01	2.50858643995965
1995-01-01	2.48864776311490
1996-01-01	2.48812786893374
1997-01-01	2.48153934318030
1998-01-01	2.46959588935160
1999-01-01	2.45244350293290
2000-01-01	2.42969920668692
2001-01-01	2.42807832133113
2002-01-01	2.42218461200699
2003-01-01	2.41208097248372
2004-01-01	2.39786287464520
2005-01-01	2.38010996217269
2006-01-01	2.37415125425178
2007-01-01	2.36730836115425
2008-01-01	2.35787994349114
2009-01-01	2.34323110792425
2010-01-01	2.32345824070223
2011-01-01	2.31032680920608
2012-01-01	2.29319636677339
2013-01-01	2.28059560725800
2014-01-01	2.28338172154969
2015-01-01	2.30631381507902
2016-01-01	2.34944338346279
2017-01-01	2.40455398606905