Year	Ratio
1970-01-01	0.110749997198582
1972-01-01	0.123099997639656
1974-01-01	0.114309996366501
1976-01-01	0.142749994993210
1977-01-01	0.159099996089935
1978-01-01	0.162619993090630
1979-01-01	0.164079993963242
1980-01-01	0.165309995412827
1981-01-01	0.165910005569458
1982-01-01	0.279130011796951
1983-01-01	0.232879996299744
1984-01-01	0.226309999823570
1985-01-01	0.242990002036095
1986-01-01	0.243100002408028
1987-01-01	0.226630002260208
1988-01-01	0.190919995307922
1989-01-01	0.193389996886253
1990-01-01	0.194199994206429
1999-01-01	0.490200012922287
2000-01-01	0.491420000791550
2001-01-01	0.527809977531433
2002-01-01	0.486519992351532
2003-01-01	0.487639993429184
2004-01-01	0.477800011634827
2005-01-01	0.521449983119965
2006-01-01	0.554600000381470
2007-01-01	0.552770018577576
2008-01-01	0.552779972553253
2009-01-01	0.598819971084595
2011-01-01	0.693250000476837
2012-01-01	0.722079992294312
2014-01-01	0.737439990043640
2016-01-01	0.701279997825623