VPN Traffic Question - how much data does the connection use?

Hi, I’m looking to find out if merely being connected to a VPN, and not transmitting files, uses up data, and if so, how much?

The closest thing I found was a 2020 article which said when transmitting data, overhead can be added up to 15%.

Please exclude thoughts about any AV updates, patches, etc that might be received - I’m only asking about data usage from the connected, but “inactive” (from user point of view, as in they aren’t browsing, checking email, copying files, etc) VPN traffic uses up.

Thank you!

bump (does reddit work that way?)

Thank you… doesn’t seem too bad, makes sense.