Port traffic - Country rankings:
The average for 2017 was 5670782.83 containers.The highest value was in China: 213719920 containers and the lowest value was in Dominica: 7553 containers. Below is a chart for all countries where data are available for: Port traffic.
Number of 20-foot containers passing through the ports, 2017
(containers, Source: Containerisation International, TheGlobalEconomy.com)