Ann: Results Presentation - Full Year Results, page-23

The main element in their business model remains the gap between what they pay to office owners and the rents SRV charge to its customers (=co workers) :
- lease revenues of 224 m$ for SRV,
- vs lease expenses and other occupancy expenses of 147 m$.

Another way to say it : when SRV pays 100 $ to an office owner, it is able to charge 152 $ to its customers.
And this calculation is based on an office occupancy rate of around 70 %.
So the potential at 100 % occupancy rate would be much higher and would correspond to a revenue of twice what they are charged by their owners.

Of course, this is a very basic calculation which ignore the service business and the other costs for SRV (in particular marketing expenses and administrative expenses).