The tornado death toll for 2011 is now 520. Until now, the highest recorded death toll in a single year was 519 in 1953. There were deadlier storms before 1950, but those counts were based on estimates and not on precise figures.
Missouri officials said the number of peoples still unaccounted for since the tornado is now at 105. From that number, nine people were reported dead by their families, but state officials have yet to confirm.
The state has been working to pare down the list of people missing and unaccounted for in the wake of the deadliest single U.S. twister in more than six decades.
The tornado - an EF5 packing 200 mph winds - was the deadliest since 1950 and more than 900 people were injured.
Twisters took the lives of at least 15 people in three other states, including two young Oklahoma boys.
The Associated Press contributed to this story