Ship congestion outside the busiest U.S. gateway for trade with Asia showed glimmers of easing as port officials race to clear a backlog of arriving cargo before peak season begins in about three months.

A total of 19 container ships were anchored waiting for entry into Los Angeles and Long Beach, California, as of Sunday, compared with 21 a week earlier, according to officials who monitor marine traffic in San Pedro Bay. The bottleneck has persisted since November, peaking around 40 vessels in early February.

Another 18 container carriers are scheduled to arrive over the next three days, with nine of those expected to drop anchor and join the queue.

The average wait for berth space was 6.1 days, compared with 6.6 a week ago, according to the L.A. port. That number had peaked around 8 days in April.

The Port of Long Beach said last week volume was the strongest-ever for any April, the 10th consecutive monthly high. It was largely due to imports. Exports haven’t fared as well because shipping companies, charging record-high rates to move goods on transpacific routes, would prefer return containers to Asia empty rather than wait for U.S. exporters’ business.

At the neighboring docks of Los Angeles, the influx of ocean freight pushed the ratio of imports to exports to a record 4.3 to 1, Executive Director Gene Seroka said on a webcast last week. L.A. also had its best April ever and is on track to hit a long-time 12-month volume target of 10 million 20-foot equivalent units of containers in its fiscal year ending June 30, he said.

Seroka signaled confidence the port could reach another goal — having “few if any” ships needing to wait at anchor by June 1, so the port is ready when volume picks up for retailer restocking season in August. “I like our chances right now and I think we’re going to keep chipping away,” he said.