I'd expect 300-500mbps, at least for a single client on 5 GHz.
The actual number is influenced by all sorts of things including RF interference, channel size, device type/chipset, device drivers/OS, device config (inc. power saving, as mentioned by @PhilipDAth) exact positioning/angle of the device to the AP, AP mounting, AP radio config, number of clients connecting/using the SSID/AP, etc.
You may want to test the bandwidth with multiple similar, ideally identical, devices at the same time to see if this might be a client-related limitation.
Out of curiosity, is there a reason why speeds of over 300mbps+ per wireless client are important to your organization? Video streaming maxes out at 20-30mbps.