Year	Ratio
1971-01-01	0.694949984550476
1972-01-01	0.717739999294281
1982-01-01	0.473489999771118
1983-01-01	0.486349999904633
1998-01-01	0.767570018768311
1999-01-01	0.743160009384155
2000-01-01	0.804019987583160
2001-01-01	0.766120016574860
2002-01-01	0.813570022583008
2008-01-01	0.750129997730255
2009-01-01	0.744249999523163
2010-01-01	0.665579974651337
2011-01-01	0.628859996795654