* Country: Employment laws and cultural norms regarding teen employment differ greatly across countries.
* Year: Economic conditions influence the availability of jobs for teens.
* Definition of "working": Are we talking about part-time jobs, summer jobs, or any paid work? Volunteer work is often excluded.
* Age range: The definition of "teen" can range from 13 to 19.
To get a precise number, you'd need to specify these factors and consult detailed labor statistics from the relevant country's government agencies (like the Bureau of Labor Statistics in the US). Even then, exact figures are difficult to obtain due to the informal nature of some teen employment.