The US Census Bureau has made its database of economic indicators searchable.
You can even download data for further manipulation, although I must admit being bemused by the “Download straight from website to Excel.”
I wonder if they mean “Excel” in the sense of any old spreadsheet program like people who say “photocopy” by another name, that starts and ends with an “X?” 😉
Probably not. They probably mean a specific bit of software.
Thought I would mention it as one of the many data sources from the US government that can be re-purposed for use with a topic map.
I am sure other governments make similar data sources available.
If you have a favorite one, please forward the URL, a brief description and any comments you want to make about using it with topic maps.