The U.S. Census Bureau is beginning to send reminder notice postcards to an estimated 69 million households that have not yet responded to the 2020 Census. About 53.4 percent of households across the country have already responded since invitations began arriving in mailboxes on March 12. Those households that have not yet responded to the census will receive an in-person visit by a census taker to collect their information later this summer.

Minnesota has the highest response rate, at 64 percent, followed by Iowa with 61.2 percent. Wisconsin, Nebraska and Michigan round out the top five, a...