1. A data capture system for receipt of a sequence of at least one output document object and, for each output document object, writing output data values to an output data structure, the system comprising: a data storage comprising: a positional identification storage including at least two positional data sets, each positional data set includes: i) identification of a required invoice data element; and ii) identification of a positional element value defining a location within a graphical representation of each output document object at which a text string representative of a value of the required invoice data element is positioned; a first tier data extraction system adapted to receive each output document object, each output document object being in a in a print language format comprising a plurality of print elements, each print element including a print component and at least one position identifier value identifying a position at which the print component is rendered within a graphical representation of the output document object, each print component being one of: i) a text string representing a value of an invoice data element; and ii) a graphic image, the first tier data extraction system being further adapted to, for each received output document object: for each required invoice data element: obtain the identification of the positional element value from the positional data set that includes, as its invoice data element, identification of the required invoice data element; if the output document object includes a qualifying text string, write an output data value to the output data structure in association with identification of the required invoice data element, the output data value being one of: i) at least a portion of the qualifying text string; and ii) a numerical value represented by at least a portion of the qualifying text string, wherein a qualifying text string is a text string of a print element that includes a position identifier value that is within a predetermined variance from the positional element value of the positional data set; and if the output document object does not include a qualifying text string, identifying the output document object for tier two processing; a second tier data extraction system adapted to receive, for each output document object identified for tier two processing, a tier two document, the tier two document being the graphical representation of the output document object, the second tier data extraction system being further adapted to: perform character recognition on the tier two document and construct a plurality of character recognition data sets, each character recognition data set associating a recognized character string within the tier two document and an identification of its location within the tier two document; and for each required invoice data element for which the first tier data extraction system failed to write an output data value to the output data structure: obtain the identification of the positional element value from the positional data set that includes, as its invoice data element, identification of the required invoice data element; and if a character recognition data set includes a qualifying recognized character string, write an output data value to the output data structure in association with identification of the required invoice data element, the output data value being one of: i) at least a portion of the qualifying recognized character string; and ii) a numerical value represented by at least a portion of the qualifying recognized character string, wherein a qualifying recognized character string is a recognized character string of a character recognition data set that includes a position identifier value that is within a predetermined variance from the positional element value of the positional data set.