Does the adapter use power when there's no phone connected?

Hi all,

I was wondering: Does the Apple poweradapter consume electricity, when there's no iPhone (or iPad etc.) connected to it?

I leave my adapters and cables in a poweroutlet all the time, which I can turn off but I was just curious about this. I read different things all over the internet, so I thought it would be best to ask my question here.

I have the original Apple 10W adapters, with the lightning usb cable, iPhone 5 and iPad 4. I live in The Netherlands by the way, if that makes any difference.

Thanks!

Stefan