Gordon Ltd., a 100% owned British subsidiary of a U.S. parent company, reports its financial statements in local currency, the British pound. A local newspaper published the following U.S. exchange rates to the British pound at year end:

Current rate $1.50
Historical rate (acquisition) $1.70
Average rate $1.55
Inventory (FIFO) $1.60

Which currency rate should Gordon use to convert its income statement to U.S. dollars at year end?