The Subnational Government Structure and Finance Dashboard displays comparable graphs on the institutional organisation and public finance at the subnational government level for 38 OECD member countries. The graphs show the weighted averages for unitary and federal countries, as well as the average for the European Union and the OECD for the latest year available.
This section includes graphs on debt as a percentage of total public debt. You may find the full dataset here: Subnational government budget balance and debt.
The data is also available in PDF format.