Start with the geography your firm actually serves
The 2020–2024 ACS five-year population estimate is 122,634, with a margin of error of 84. For attribution, the useful implication is narrower: your firm should decide how it wants to distinguish Arvada inquiries from inquiries elsewhere in either county, the broader metro area or Colorado. A report that combines all of those areas may obscure which service pages or channels are associated with the matters you want.
Recommended approach
Bring your preferred service area definitions to a consultation. Ask whether reporting can be reviewed by the geographic distinctions your firm uses, and decide which geography belongs in intake, source review and outcome reporting.
