What is the typical range of efficiency values for a power transformer?

Is efficiency calculated as real power in divided by real power out or do you include reactive power as well?

 

The efficiency of a power transformer is defined as the ratio of output power to input power:
(power secondary winding / power primary winding)*100 [%].
But what type of electrical transformer you want to calculate efficiency? Low power single-phase transformers, three phase power transformer ...?