If you are using Microsoft Excel to manage numerical data, at some point you're inevitably going to display percentages. Doing so can give you a new insight, or make summarizing heaps of data a bit ...
Learn how GROUPBY passes both subset and full arrays into LAMBDA in Excel, letting you compute percent shares fast and explain results clearly.
Tables, named ranges, line breaks, modern functions, and helper columns make Excel formulas easier to read, audit, and fix.