Start with the geography your firm actually serves
Mexico is recorded as a municipality in Audrain County, Missouri. For AI Answering, the important implementation question is therefore not how many people live in the municipality. It is which callers your firm accepts from Mexico, Audrain County and any other area you deliberately serve, and how those callers should be handled when the office cannot answer.
Recommended approach
Bring your actual service-area policy to the review. Define whether the phone system should treat Mexico callers, Audrain County callers and callers from outside the county differently. Use your own call records, missed-call records and matter-intake records to decide what should be measured.
