There are many different numbering schemes for assigning numbers to entities. These generally require an agreed set of rules, or a central coordinator.
Numbering schemes include:
The E.164 numbering plan for telephone numbers, including:
... 100 females there are 104.2 males. For every 100 females age 18 and over, there are 97.8 males.
The median income for a household in the town is $78,399, and the media ...