Power Pivot - Calculate difference and % difference

Could get all fancy but if simple one off. Something like this.

Avg2020:=calculate(....,filter(all(table,date),year=2020)

Same for 2021

Difference measure just subtract the two measures. Percent difference measure is divide(difference measure,2020measure)

Hi All

this is what i did eventually:

CALCULATE([Average cost, TableName(column) = "2020"]) 

CALCULATE([Average cost, TableName(column) = "2021"]) 

% Difference = 

=IF(

OR([Avg Part Cost 2020]<=0, [Avg Part Cost Post 2021]<=0),"na",[Avg Part Cost 2021]-[Avg Part Cost 2020])