Our data comes from the CPI (Consumer Price Index) report released by the Bureau of Labor Statistics. New reports are released monthly.
For conversions involving the current year, we use the latest CPI number. For example, to convert between 2023 and 5 years ago, we'd take the latest CPI number and compare it to the number from 60 months prior.
The latest CPI number is from October 2023.
For conversions that do not involve the current year, we use an average (mean) of all 12 months from the CPI report of the two years being compared.