I got the same thing from the Department of Commerce (Census Bureau) in 2009. The letter was addressed to “Current Resident.” I was selected for a household expenditure survey. They want to know how you spend every nickle every month. They want to see your utility bills, cable TV bills, even your ATM withdrawals. It is unbelievable. I told other people about it and almost no one believed me. I stonewalled them. They pounded on my door several times. I told them to f@*! off. I asked it they had a search warrant signed by a judge. Too bad I don’t have a large dog. The letters kept coming. They say they are from the government and they are here to help me. I sent the letters back with handwritten notes on them. I said I am sick with cancer. They don’t care. Finally after several months they gave up. I was prepared to go to jail rather than give in to this.
I'd tell them I spend it all on porn.