Usage edit
This template is still under development.
To use: {{formatnum:{{Meta-Population|Country|State/Province/City|City}}}}
Use ISO 3166-1 alpha-3 standards for the country code. For US States, use the last two letters in the ISO 3166-2:US standard (which for States is the same as their U.S. postal abbreviation).
Example, {{formatnum:{{Meta-Population|USA|OK|Tulsa}}}} returns 385,635.