Year	Ratio
1971-01-01	0.0831099972128868
1972-01-01	0.1002399995923040
1973-01-01	0.1257199943065640
1974-01-01	0.1263899952173230
1975-01-01	0.1568000018596650
2002-01-01	0.6367999911308290
2003-01-01	0.6369799971580510
2004-01-01	0.6371099948883060
2005-01-01	0.6567900180816650
2006-01-01	0.7218599915504460
2007-01-01	0.7870799899101260
2008-01-01	0.7939100265502930
2009-01-01	0.7903100252151490
2010-01-01	0.8152700066566470
2011-01-01	0.7374399900436400
2012-01-01	0.7761200070381160
2013-01-01	0.7775300145149230
2014-01-01	0.7829499840736390
2015-01-01	0.8071100115776060