Year	Ratio
1971-01-01	0.468019992113113
1972-01-01	0.533940017223358
1973-01-01	0.529929995536804
1974-01-01	0.461470007896423
1975-01-01	0.548600018024445
1981-01-01	0.722010016441345
1984-01-01	0.756120026111603
1985-01-01	0.899800002574921
1986-01-01	0.761370003223419
1987-01-01	0.799759984016418
1988-01-01	0.803529977798462
1989-01-01	0.809660017490387
1990-01-01	0.705160021781921
1991-01-01	0.730359971523285
1992-01-01	0.849579989910126
1993-01-01	0.878359973430634
1994-01-01	0.828209996223450
1998-01-01	0.860230028629303
1999-01-01	0.856060028076172
2000-01-01	0.857290029525757
2002-01-01	0.823010027408600
2003-01-01	0.823409974575043
2004-01-01	0.887019991874695
2007-01-01	0.899150013923645
2008-01-01	0.921720027923584
2011-01-01	0.846090018749237
2013-01-01	0.942019999027252
2014-01-01	0.931689977645874