Download speeds with router

I have a Belkin 4 port wired router connected to 4 PCs on one side and a 2mbps cable modem on the other. If the internet is coming into the cable modem at 2mbps than what speed is the router serving the data to the 4 PCs at?

I thought as the NIC is a 10/100 it would probably be 100 mbps but can’t measure it. Any internet speed measurements just measure the speed to the cable modem (I think).

Any ideas?
Thanks
Bruce