WASHINGTON D.C.: The volume of container imports handled by U.S. ports has dropped sharply after more than two years of surging demand, raising concerns about when the sector will hit rock bottom.

According to data tracked by Descartes Datamyne, container import volume going through all U.S. ports reached an all-time high in May, but declined slightly before plunging in August and September to levels close to those seen in 2019, before the pandemic and a surge in demand for shipments of furniture, clothing and appliances.

Goods transported in ocean containers make up some 25 percent of U.S. imports and many consumer purchases, which account for as much as 70 percent of U.S. economic activity.

As retailers raced to meet soaring demand for goods, volume surged as much as 40 percent from 2019 levels during the COVID-19 pandemic, clogging ports and causing delays that led to late deliveries of all types of items.

As part of a "dashboard" to monitor the distress in the distribution of goods and a contributor to higher prices, the Biden administration supply chain task force had tracked container imports as recently as March.

Believing that consumers are reverting to their traditional spending split of 70 percent on services and 30 percent on goods, transportation economist Walter Kemmsies said, "We are going back to 2019," according to Reuters.

The August and September pullbacks in the volume of container imports is due to retailers, such as Walmart and Amazon.com, cancelling billions of dollars of orders earlier this year, he added.

US retailers have large amounts of excess apparel, personal computers, small appliances and holiday decor, and are desperate to clear exiting product supplies, so they will likely hold back on new orders.

In a weekly update, shipping consultant Jon Monroe said, "Warehouses are full. Until importers clear their inventory, expect overseas orders to be weak."