Aggregate/sum data records

We have a data record that is populated from a CSV file, one of the fields is "number of customers", the data records are displayed in a table using an asset listing.


We have a request to display aggregate data from the data record i.e. "total number of customers".



Is there a Matrix solution to aggregating data record or asset listing values? i.e. not JavaScript?



I have investigated the asset listing keyword modifiers - add, XSLT but can't see ho these can be used to solve this problem.



Any suggestions?



Thanks.