American Community Survey (ACS) multiyear estimates with dollar values are adjusted for inflation to the final year of the period. For example, the 2014-2018 ACS 5-year estimates are tabulated using dollars adjusted to 2018. Multiyear estimates for dollar-denominated data are adjusted using the Consumer Price Index Retroactive Series (R-CPI-U-RS) annual averages.
Learn more about using dollar-denominated data in section 10, "Using Dollar-Denominated Data," in the General Data Users Handbook.