With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cnatInterfaceStatsEntry
cnat Interface Stats Entry
1.3.6.1.4.1.9.10.77.1.3.3.1
Each entry of the cnatInterfaceStatsTable represents stats pertaining to one interface, which is identified by its ifIndex.
Back to CISCO-IETF-NAT-MIB MIB page.
IPHost Network monitor allows you to monitor cnatInterfaceStatsEntry on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco multiplexers right now.