From the American Journal of Transportation:
U.S. West Coast ports increased their market share in 2016 indicating losses to East Coast and Gulf ports are being reversed.
According to the PMSA’s (Pacific Merchant Shipping Association) West Coast Trade Report, the year 2016 saw:
“U.S. West Coast (USWC) ports increase their collective share of containerized trade through seaports on the U.S. mainland. Outbound or inbound, value or weight, the Pacific ports gained market share last year.” The PMSA report said the USWC containerized import market share by value rose “from 47.4% in 2015 to 49.2% in 2016.”