In the past, Denon (and I am sure there are others) did provide the primary current draw in their spec sheet and manuals. For example, AVR-3805 7.1A, AVR-4308 8.1A. That's at 120 V, so at the output rail, it could be around 15 to 18A total depending on the maximum rail voltage. The problem is, just like the power consumption specification, they don't tell you the conditions they based the figures on, that is, continuous, X % of rated output, or maximum output and at what load impedance, distortions level etc.
Yamaha sometimes provide two numbers, the power consumption, and the maximum power consumption that is typically > 2X the power consumption, but we still don't know anything about the duration, distortions allowed etc.
Given that there is no apparent standards they could all adhere to, our best bet to stick with bench test results, mostly by S&V and AH. The British Home Cinema choice and AVtech Miller Audio research used to do similar lab measurements but appeared to have stopped a few years ago.