Yes, of course in principle you can store the GDP/person of a country over a time interval (e.g. from World Bank) in the database :
- Activity: All economic activities (defined as those that have monetary labour costs, net taxes and/or net operating surplus)
- Flow-object: Value added (= labour costs, net taxes and net operating surplus)
- Flow-property: Monetary value
- Property-relation: Person
but normally we would calculate that by summing the value added over all activities in the database for that country in that time period and dividing by the population, which is why I said it was a query output. But you are right that you could use this calculated value to compare with that of the World Bank.
And likewise for the CO2 emission / country:
- Activity: All
- Flow-object: carbon dioxide
And likewise the recycling rate for a material of a country could be stored as the output of the national market for that material for recycling with a property-relation to the output of the market for the material (virgin + recycled).
Also in these cases, the external "raw" value can be compared to the calculated from the more specific data in the database. But behind these "raw" data from e.g. World Bank, there are of course other databases that have summed over other specific data...