A computer readable storage medium includes executable instructions to analyze a query associated with a report to identify query clauses. The query is applied against a data source that does not have a specified time dimension. An optimized audit log is formed from an existing audit log to store data changes of interest at the data source and temporal values associated with the data changes, where each data change corresponds to a query clause. A state table is constructed to specify the state of each query clause. Records in the optimized audit log are processed by temporal value to produce updated state tables. Transition tables are derived from the updated state tables to associate temporal values with data changes at the data source that impact a result produced by the query. Trend data is then supplied from the transition tables.