Year	Ratio
1971-01-01	0.742910027503967
1972-01-01	0.767289996147156
1973-01-01	0.776929974555969
1974-01-01	0.787699997425079
1975-01-01	0.794120013713837
1976-01-01	0.806720018386841
1977-01-01	0.815850019454956
1978-01-01	0.819999992847443
1979-01-01	0.831200003623962
1980-01-01	0.836340010166168
1981-01-01	0.837509989738464
1982-01-01	0.840719997882843
1983-01-01	0.840460002422333
1984-01-01	0.842329978942871
1985-01-01	0.840319991111755
1986-01-01	0.844330012798309
1987-01-01	0.850470006465912
1988-01-01	0.853590011596680
1989-01-01	0.855000019073486
1990-01-01	0.857919991016388
1991-01-01	0.860849976539612
1992-01-01	0.920029997825623
1994-01-01	0.900009989738464
1995-01-01	0.901049971580505
1996-01-01	0.859160006046295
1997-01-01	0.871529996395111
1998-01-01	0.833010017871857
1999-01-01	0.825360000133514
2000-01-01	0.855780005455017
2001-01-01	0.870710015296936
2002-01-01	0.863219976425171
2003-01-01	0.855329990386963
2004-01-01	0.858569979667664
2005-01-01	0.839839994907379
2006-01-01	0.839519977569580
2007-01-01	0.861039996147156
2008-01-01	0.860650002956390
2009-01-01	0.866900026798248
2010-01-01	0.864889979362488
2011-01-01	0.870389997959137
2012-01-01	0.877160012722015
2014-01-01	0.891529977321625
2015-01-01	0.898779988288879
2016-01-01	0.900759994983673