Probably, Vlan2 is not layer3 interface or you have not enabled collection of layer2 statistics.

Try the command "show ip interface brief" to display brief summary of IP status and configuration. Probably Vlan2 has not assigned IP address or is in the down status. You can enable collection of layer2 statistics via the command: "ip flow ingress layer2-switched vlan 2 " where 2 is vlan id (you can also use list or range of vlans).