This process is currently manual and cumbersome, which explains why they're only updated every few months (or when someone needs a pretty chart).
It would be really nice to have a tool (probably in Tool Labs) to generate the metrics automatically on a more frequent basis. A stand-alone tool would also make it easier to generate up-to-date charts automatically.
This would also be an opportunity to start tracking and charting other metrics, like the top contributors and translators (this was only done once). The Translate API also provides access to interesting data about the translations available (and their completion rate) that could be analyzed and charted; at the moment, doing so manually is prohibitively time-consuming.
Timely tracking and charting of those metrics would make it easier to identify trends, issues and successes.