Elva Bova, Robert Dippelsman, Kara Rideout and Andrea Schaechter review the evidence on governments’ non-financial assets in an IMF working paper. An excerpt from the abstract:

… state-owned nonfinancial assets across 32 economies, with particular focus on the advanced G-20 economies. We find that reported nonfinancial assets comprise mostly structures (such as roads and buildings) and,when valued, land. These assets have increased over time, mostly due to higher property and commodity prices, and are, in large part, owned by subnational governments. Many countries have launched reforms with a view to streamlining public administrations, but receipts and savings have been rather small so far. Governments tend to consider relatively small sets of assets to be disposable …