Year	Ratio
1971-01-01	0.287220001220703
1972-01-01	0.312629997730255
1973-01-01	0.310339987277985
1974-01-01	0.322730004787445
1975-01-01	0.343019992113113
1976-01-01	0.322620004415512
1977-01-01	0.362540006637573
1978-01-01	0.385170012712479
1979-01-01	0.372110009193420
1980-01-01	0.387529999017715
1986-01-01	0.372970014810562
1987-01-01	0.368160009384155
1988-01-01	0.387239992618561
1990-01-01	0.405200004577637
1992-01-01	0.268519997596741
2003-01-01	0.803439974784851
2004-01-01	0.788330018520355
2005-01-01	0.869759976863861
2006-01-01	0.847549974918365
2007-01-01	0.846040010452271
2008-01-01	0.844649970531464
2009-01-01	0.843469977378845
2011-01-01	0.920289993286133
2012-01-01	0.953429996967316
2013-01-01	0.977129995822906
2014-01-01	1.060850024223330
2015-01-01	0.872269988059998
2016-01-01	0.870389997959137