Shipping containers are measured in “twenty-foot equivalent units“, with the capacity of ships and warehouses given in TEU. As of ~2018 the largest containers ships can hold about 22,000 TEUs- and globally there are 5,222 ships as of April 2018 that can carry a total of 21.5 million TEUs. (Stats from Costamare, Inc.)
In Q2 2020, owners ordered 98 container ships, representing additional capacity of 1M TEU. The covid-19 impacts (labor, social distancing,etc.) led to a 40% reduction in U.S. warehouse labor supply, slowing warehouses ability to process (turn) containers.