Download all statistics for a build configuration

I'd like to look at the change in average test duration over time; that is, for each build under a given build configuration, I'd like to calculate sum(test_duration) / test_count and export to e.g. Excel.

I can see this information in the build configuration's Statistics tab, going all the way back to when the build configuration was created. I can see some of this information in the database, by joining the history, stats and test_info tables. But the information in the database has been cleaned up and I can only see recent builds. The light_history table contains all of the builds, but I can't see where test information is kept.

Is there a way to get the raw data used by the charts on the Statistics tab?

Thanks,

Tim