From a forwarding perspective, there are two kinds of entities, tunnel and cross-connects.
For tunnels, the statistics refer to the number of packets or bytes pushed into the MPLS tunnel. It could be any kind of traffic, such as IPoMPLS or VPLS.
Cross-connects are entities programmed on transit routers for forwarding labeled traffic. For a cross-connect, traffic is measured as the number of packets coming into the router with the particular label for which the cross-connect is programmed.