Oh I see, I also can't find the corresponding OIDf that matches the Mbps column in CPView.
I'm pretty sure CPView came down the Mbps values using the PPS (packets per second) and Mbits values.
But (and here's the catch) the PPS value depends on how the gateway is configured for packet inspection (maybe if it's an appliance involved you can check out DPI throughput in the specs sheets and get to a sloppy approximation).
Roughly we can say, as an example:
For 2000 PPS and using the default MTU size (1500 bytes), is 3000000 Bytes/sec (2000*1500*8), which is equivalent to 24000000 bits/sec (24 Mbps).
But I believe we've another catch here: the packet size I used (the default MTU size), and as it depends to the inspection done by the gateway, in real life scenario it should be never close to 1500 bytes.
Maybe some CP guy here involved in CPView development could tell us how the Mbps calculation is done.