Year	Ratio
1971-01-01	1.20776998996735
1981-01-01	1.30770003795624
1986-01-01	1.38724994659424
1991-01-01	1.22750997543335
1992-01-01	1.22477996349335
1993-01-01	1.23594999313354
2001-01-01	1.30090999603271
2002-01-01	1.35101997852325
2003-01-01	1.30516004562378
2004-01-01	1.36828005313873
2005-01-01	1.37329995632172
2006-01-01	1.36913001537323
2007-01-01	1.36222994327545
2008-01-01	1.36097002029419
2009-01-01	1.35118997097015
2011-01-01	1.33683001995087
2012-01-01	1.27392005920410
2013-01-01	1.23996996879578
2014-01-01	1.20481002330780
2015-01-01	1.21122002601624
2016-01-01	1.19532001018524