But such data from the Census Bureau are seldom as straightforward as they seem.
Median income is measured by taking a survey.
The results from a small sample of households are projected onto the entire nation. Every survey projection runs into the problem of sampling error. Because of small variations from one sample to another, there is always a little movement up or down when the incomes of last year's sample are compared to this year's. But these differences do not reflect actual changes across the entire population. In the remaining 39 states, median income was either unchanged or decreased.