API: how to get shipping_cost from order (it is not returned)

I am trying to get shipping cost from my orders via api call.
However the field shipping_cost is not even present in resulting json.
Any reason why this field is not returned and how to enable this?

Hi!

Please make sure that you specify the order in your API request, so that it does not point to all orders:

/api/orders/

but to the specific order:

/api/orders/97