Unfortunately, this can vary greatly. For example, information technology (IT) staffing involves a variety of positions, all of which include variables like technologies, seniority, duration of position, and type of role (contract vs. permanent). Any of these factors can change the length of time needed to get qualified candidates to you for review.
In addition, there are multiple other factors such as market location. For example, it might be easier to find someone to work remotely instead of in the office, or it might be easier to locate candidates to work in a major metropolitan area as opposed to a rural office location. Lastly, your recruiter may or may not be in a position to have already identified candidates based on their staff’s existing connections.
While the above answer doesn’t exactly give an expected duration, please do bring this topic up with your staffing firm Account Manager. They should be able to set expectations based on current conditions relating to your firm and the skill set needed for this hire.