Two Louisiana parishes devastated by repeated hurricanes and two rural Nebraska counties had among the highest rates of households with missing information about themselves during the 2020 census that required the U.S. Census Bureau to use a last-resort statistical technique to fill in data gaps, according to figures released Thursday by the statistical agency.

Allen and Calcasieu parishes were hit hard by Hurricanes Laura and Delta in September and October 2020 during the last weeks of the once-a-decade census that determines how many congressional seats each state gets, provides the data for redrawing political districts and helps determine $1.5 trillion in federal spending each year.

Along with rural Logan and Banner counties in Nebraska, the parishes had rates of homes with missing information that required the statistical technique to be used ranging from 8.4% to 11.5%. The technique called count imputation uses information about neighbors with similar characteristics to fill in data gaps in the head count.

Nationwide, 0.9% of households were counted using the technique during the 2020 census.

Typically, imputation provides the least reliable information about a household. Information from the people living in a home, who either fill out a census form or answer questions from a door-knocking census taker, provides the best information about a household.

If firsthand information can’t be obtained, the Census Bureau next turns to administrative records such as IRS returns, or census-taker interviews with proxies such as neighbors or landlords. Imputation is used after those other avenues have been exhausted.