Methodology · the 2019/2020 seam
Within-vintage growth only.
The 2010–2019 series (Census Vintage 2019) and the 2020–2025 series (Census Vintage 2025) are two independent estimates of different reference dates, produced by two methodology generations. V2019 extrapolated forward from the 2010 census; V2025 re-based to the 2020 census. The seam between them mixes a methodology shift with real population change.
Every growth and decline number on this site stays inside a single vintage. We publish 2020 base → 2025 estimate as the modern growth metric. We do not publish a single 2010 → 2025 growth number.