Year	Ratio
1970-01-01	0.442339986562729
1971-01-01	0.502879977226257
1973-01-01	0.722100019454956
1974-01-01	0.696680009365082
1975-01-01	0.653060019016266
1977-01-01	0.845009982585907
1978-01-01	0.938269972801209
1979-01-01	0.848079979419708
1981-01-01	0.945550024509430
1982-01-01	0.972090005874634
1983-01-01	0.927150011062622
1984-01-01	0.910279989242554
1985-01-01	0.995970010757446
1986-01-01	1.062260031700130
1987-01-01	1.362200021743770
1988-01-01	1.568519949913020
1989-01-01	1.586019992828370
1990-01-01	1.435299992561340
1991-01-01	1.514430046081540
1992-01-01	1.261630058288570
1993-01-01	1.333719968795780
1994-01-01	1.311300039291380
1995-01-01	1.337540030479430
1996-01-01	1.301130056381230
1999-01-01	1.857429981231690
2000-01-01	1.697350025177000
2001-01-01	1.809839963912960
2002-01-01	1.431139945983890
2003-01-01	1.632050037384030
2005-01-01	1.353520035743710
2006-01-01	1.263229966163640
2012-01-01	1.485419988632200
2013-01-01	1.435860037803650
2014-01-01	1.427800059318540
2015-01-01	1.503890037536620