=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-Jun-1991
Johnston Island     760/011 RLR(1975) is 9.9m below BMNo21 1964
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 24-Nov-2011
Using information from the NOAA website the RLR diagram has been revised. Primary benchmark is now NO 13 1955 2.85m above gauge datum this appeared as a secondary benchmark on the original diagram. Previous Primary benchmark NO 21 1964 remains in the NOAA reports.