I am flying from LHR to IAD on Thursday. This is the seat availability which is showing for my flight:

F9 C9 D9 Y9 B9 M9 H9 Q9 V9 W9 S9 T0 K9 L9

I'm a complete novice when it comes to reading this type of data. Could someone give me a bit of a primer on how to intepret these statistics? Interestingly, they're still offering cheap fares only 3 days in advance...is this unusual too?

Thanks,

David