Year	Ratio
1978-01-01	1.75450003147125
1979-01-01	1.87477004528046
1980-01-01	2.01904988288879
1981-01-01	2.02078008651733
1982-01-01	2.08749008178711
1983-01-01	1.87773001194000
1984-01-01	1.71849000453949
1985-01-01	2.10928010940552
1986-01-01	1.93300998210907
1987-01-01	2.13146996498108
1988-01-01	2.57768011093140
1989-01-01	3.36332011222839
1990-01-01	3.93792009353638
1991-01-01	4.18074989318848
1992-01-01	5.40583992004395
1993-01-01	4.01380014419556
2007-01-01	2.85283994674683
2008-01-01	2.86919999122620
2009-01-01	2.87164998054504
2010-01-01	2.79444003105164
2011-01-01	2.37314009666443
2012-01-01	2.44990992546082
2013-01-01	2.32374000549316
2014-01-01	2.24795007705688
2015-01-01	2.13646006584167
2016-01-01	1.99302005767822