Optimize — % of Total per Region without Repeating the Range

A teammate's "% of total revenue per region" formula in column G repeats the same ranges three times across two SUMIFS/SUM calls:

=SUMIFS($C$2:$C$16, $B$2:$B$16, F2) / SUM($C$2:$C$16) * 100

The Revenue range $C$2:$C$16 appears twice; the Region range $B$2:$B$16 appears once. As the table grows, every range gets re-typed, and an out-of-sync range ($C$2:$C$15 in one call, $C$2:$C$16 in the other) is a silent corruption waiting to happen.

Refactor with LET so each range is bound once to a readable name, and the formula body composes the SUMIFS and SUM in terms of those names.

Columns A–C contain TxID, Region (North/South/East/West), and Revenue for 15 transactions. The region labels are pre-populated in column F (F2=North → F5=West) and the PctOfTotal header sits in G1.

Your task:

1. In column G (PctOfTotal), write a LET-bound version: bind revenueRange and regions to the data ranges, then compute SUMIFS(revenueRange, regions, F2) / SUM(revenueRange) * 100 in terms of those names. Optionally bind total and part for full readability.
2. Drag-fill from G2 → G5.

Graded cells: G2 (North → 20), G4 (East → 30), G5 (West → 10).