Year	Ratio
1992-01-01	0.997489988803864
1993-01-01	0.991710007190704
1994-01-01	0.978770017623901
1995-01-01	0.971369981765747
1996-01-01	0.968069970607758
1997-01-01	0.960839986801147
1998-01-01	0.997940003871918
1999-01-01	0.997820019721985
2000-01-01	1.001649975776670
2001-01-01	0.992129981517792
2002-01-01	0.979499995708466
2003-01-01	0.967779994010925
2004-01-01	0.960929989814758
2005-01-01	0.965659976005554
2006-01-01	0.961769998073578
2007-01-01	0.965699970722198
2008-01-01	0.959609985351563
2009-01-01	0.963789999485016
2015-01-01	0.975530028343201
2016-01-01	1.003090023994450