1. A method, in a data processing system comprising a processor and a memory, for performing tabular data correction in a document, the method comprising: receiving, by the data processing system, a natural language document comprising tabular data; analyzing, by the data processing system, the tabular data within the natural language document to identify at least one portion of the tabular data comprising an erroneous or missing data value; determining, by the data processing system, for the at least one portion, a functional dependency of the at least one portion of the tabular data on one or more other portions of the tabular data by reference to the natural language document; determining, by the data processing system, for the at least one portion, a correct data value for the erroneous or missing data value of the at least one portion of the tabular data based on the determined functional dependency of the at least one portion; modifying, by the data processing system, the tabular data to replace the erroneous or missing data value with the correct data value and thereby generate a modified tabular data structure; and performing, by the data processing system, a processing operation on the modified tabular data structure to generate an resulting output.