17. The apparatus of claim 11 , wherein the instructions cause the processor to analyze the tabular data to identify at least one portion of the tabular data comprising an erroneous or missing data value at least by: analyzing the at least one portion of the tabular data to determine whether the at least one portion of tabular data comprises a regular structure having a repeated pattern of data or an identifiable dependency between cells in the at least one portion of the tabular data; and in response to a regular structure being identified in the at least one portion of the tabular data, performing further analysis to determine if one or more cells within the at least one portion of the tabular data do not conform with the regular structure.
11. An apparatus comprising: a processor; and a memory coupled to the processor, wherein the memory comprises instructions which, when executed by the processor, cause the processor to: receive a natural language document comprising tabular data; analyze 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; determine, 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; determine 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; modify 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 perform a processing operation on the modified tabular data structure to generate a resulting output.