If you look at page 12 here (https://www.uspsoig.gov/sites/default/files/reports/2026-09/...) the USPS estimates 30,000,000 fraudulent labels are/were used per month. The accused sold 5 million labels via Labelsbank.com over a ~2 year period (https://web.archive.org/web/20240326164928/https://labelsban...). That's ~208,000/m so his scam would represent 0.7% of fraudulent labels.

These numbers are rough but there you go. Your intuition is correct. Roughly 100X.