The PSAP has multiple customers, of course, but the bulk of their traffic goes to the Port of Greys Harbor, Washington. This port is on the cost, and is not not part of Puget Sound. You can get a reasonable idea of traffic on the PSAP by perusing the Port's website:

[www.portofgraysharbor.com]

The port has really done a remarkable turnaround. At one time it was largely based around the lumber trade, but of course, that industry has suffered greatly. But the Port attracted a new, modern grain export terminal, and is also an automobile export (small volume, but its a start.) And coal export has been proposed, but whether that happens is subject to greater Washington² politics.