It varies but most agencies charge 15-40% of the 1st year salary for permanent hire or 15-40% on top of the daily rate of the freelancers throughout the engagement.
So if a UK based consultant’s rate is £500 per day, the agency is likely to charge around £100 per day so the Customer pays £600 for every day the consultant works for them.
As we know, most Microsoft Dynamics 365 projects are medium to long term, so each month at that rate is a £2,000 per month uplift, or £24,000 per year for the recruiter for placing just one contractor.
In USA, the rates are hourly so if a client pays $100 per hour, the agency is likely to retain $35 (this is $280 per day, over $67,000 per year).
No need to mention that most people hire more than one consultant.