If you use the Litigation Firewall to scrub against the National DNC Registry, you may notice a significant percentage of numbers being scrubbed out. In most cases, this is completely normal, due to simple math.
As of September 30, 2024, the National Do Not Call Registry included approximately 254 million active number registrations.
Recent telecom data suggests around 300–350 million consumer phone numbers (landline and wireless) are in active use domestically. About 320 million phone numbers would therefore be a good estimate for the entire US population.
254 million DNC numbers divided by 320 million U.S. personal phone numbers currently in use means that approximately 79% of all consumer phones are on the DNC.
That means that you can expect to lose a substantial percentage of data when you scrub against the National DNC.
A 73% to 85% reduction is perfectly normal.