Add 5.260m to data values 1945-1971 to refer to RLR<br>Add 4.909m to data values 1972-1984 to refer to RLR<br>Add 5.260m to data values 1985-1986 to refer to RLR<br>Add 4.909m to data values 1987 onwards to refer to RLR<br>RLR is 10.600m below primary benchmark 61936