How long do you think it will be before we rely on drones to be used for delivery service around the world?

Question: How long do you think it will be before we rely on drones to be used for delivery service around the world?
- Keywords:
  delivery,
  drones,
  world
Asked by m4tty to Saiful, Petra, Jenny, Jawwad, Iain, Bethan on 18 Jan 2017.
- Petra Cameron answered on 18 Jan 2017:
  
  I have no idea! Although I imagine they will only be useful for small, light parcels.

Question: How long do you think it will be before we rely on drones to be used for delivery service around the world?