Year	Ratio
1970-01-01	0.611670017242432
1971-01-01	0.557780027389526
1972-01-01	0.645829975605011
1973-01-01	0.645229995250702
1974-01-01	0.680840015411377
1975-01-01	0.654479980468750
1976-01-01	0.676580011844635
1977-01-01	0.727320015430450
1978-01-01	0.704729974269867
1979-01-01	0.724389970302582
1980-01-01	0.753750026226044
1981-01-01	0.756319999694824
1982-01-01	0.775659978389740
1983-01-01	0.792770028114319
1986-01-01	0.821919977664948
1990-01-01	0.849619984626770
1991-01-01	0.851970016956329
1992-01-01	0.846350014209747
1993-01-01	0.851660013198853
1994-01-01	0.867280006408691
1999-01-01	0.926900029182434
2000-01-01	0.919179975986481
2002-01-01	0.937990009784698
2005-01-01	0.947499990463257
2006-01-01	0.959330022335052
2007-01-01	0.958559989929199
2010-01-01	0.975210011005402
2011-01-01	0.972670018672943
2012-01-01	0.979089975357056
2013-01-01	0.988770008087158
2014-01-01	0.971989989280701
2015-01-01	0.989319980144501
2016-01-01	0.987800002098084