Year	Ratio
1971-01-01	0.582769989967346
1972-01-01	0.576780021190643
1973-01-01	0.595839977264404
1974-01-01	0.616720020771027
1975-01-01	0.641059994697571
1976-01-01	0.654980003833771
1977-01-01	0.677950024604797
1978-01-01	0.677500009536743
1979-01-01	0.677399992942810
1980-01-01	0.688769996166229
1981-01-01	0.707650005817413
1982-01-01	0.721620023250580
1983-01-01	0.745150029659271
1984-01-01	0.753109991550446
1985-01-01	0.743849992752075
1986-01-01	0.755060017108917
1987-01-01	0.751240015029907
1988-01-01	0.764419972896576
1989-01-01	0.799939990043640
1990-01-01	0.786989986896515
1991-01-01	0.809530019760132
1992-01-01	0.825749993324280
1993-01-01	0.826470017433167
1994-01-01	0.965780019760132
1995-01-01	0.961179971694946
1996-01-01	0.918380022048950
1997-01-01	0.979499995708466
1998-01-01	0.969770014286041
1999-01-01	1.034540057182310
2000-01-01	1.037170052528380
2001-01-01	1.051159977912900
2002-01-01	1.099380016326900
2003-01-01	1.074589967727660
2004-01-01	1.098549962043760
2005-01-01	1.160670042037960
2006-01-01	1.219419956207280
2007-01-01	1.267930030822750
2008-01-01	1.315199971199040
2009-01-01	1.375110030174260
2010-01-01	1.396280050277710
2011-01-01	1.416900038719180
2012-01-01	1.416219949722290
2013-01-01	1.421489953994750
2014-01-01	1.401700019836430
2015-01-01	1.406790018081670