This is not an easy problem to solve. Certainly I want more things at the federal level than the authors of the constitution envisioned (currency, international diplomacy, military, etc.): some things really need to be done at the national level (like environmental regulation).
Anyway. Sure, those figures may be true for the US Congress (or not, I haven't verified), but I bet you those figures aren't even close to true for town and city councils and county government. And perhaps not even state government as well.