Daft scrutineering question - belt expiry date

[Notshortnottall]

Just looking over the car and realised my belts have an expiry date of 2015 - does this mean they expire on 1/1/15 or 31/12/15?

[jagracer]

End of 2015

[Jerry Can]

31/12/15

[Notshortnottall]

Cheers gents