Depends what you mean by "average" in the first place. There could be more folk earning a certain figure, is that the average? Do you add up everyone's wages and divide by the number of folk to get the answer? Another method is to put all the amounts in order and see what amount is in the middle.
You may think this is picky, but if eighty folk are getting £15,000 a year and twenty are getting £100,000 a year what is the 'average' amount?
You can't calculate average salary at minimum wage. It must include all full time wages, from top to bottom and the number of people earning these wages.
I used to earn about the "Average Salary" but I had to work 3 shifts and weekends to make it an "Average Salary". Without the enhancements I would have been well below the "Average Salary".
"If eighty folk are getting £15,000 a year and twenty are getting £100,000 a year what is the 'average' amount?" If you use the modal average, the answer would be $15,000 (I don't have a pound symbol).