Load (%) = Traffic (bps) / bandwidth or capacity (bps)

interface Tunnel0
 bandwidth 256
 ip address 10.10.1.1 255.255.255.252
 load-interval 30
 ....
 ....
!

csr1000v#show interfaces  gigabitEthernet 1
GigabitEthernet1 is up, line protocol is up
...
  reliability 255/255, txload 3/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full Duplex, 1000Mbps, link type is auto, media type is Virtual
  output flow-control is unsupported, input flow-control is unsupported
  ...
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  30 second input rate 1000 bits/sec, 3 packets/sec
  30 second output rate 4000 bits/sec, 1 packets/sec
     1003836 packets input, 174201781 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
    ...
     169446 packets output, 80281698 bytes, 0 underruns
     ....