Where to Find Inter-State Trade Balance?

[Cyrix]

I am looking for inter-state trade balance data, as an aggregate for each state.

For example, whether Ohio is in trade deficit or surplus with other states.

I have data for state level trades with other countries (http://www.census.gov/foreign-trade/statistics/state/index.html) but I also need trade data with other states in the US.

Does anyone know if such data exists in public sources?

Thanks.