What throttle setting does an airliner use while cruising?
(Above is the max cruise limit in standard ISA for the A320.)

It's 80.4% - 86.5% for the different weights and altitudes. Do note that 81% does not mean 81% of the available thrust. The maximum continuous thrust (MCT) at standard temperature is between 86% and 89% for the different cruise flight levels.

The colder the air, the lower the values, and vice versa for hot temperatures. If too hot above ISA, max flight level is limited for the higher weights due to MCT being the limiting factor.

For the A320 example, the thrust levers remain in the CLimb detent from thrust reduction to just before landing in normal operations.

For the 777-200, the range varies from 69% - 96.8% depending on the flight level and weight (with 86.8% - 94.7% being the optimum range). The wider range is due to the 777's wider payload/fuel range when compared to the smaller A320.