Add 9.139m to data values 1935-1958 to refer to RLR<br>Add 7.126m to data values 1959-1986 to refer to RLR<br>Add 6.126m to data values 1987 onwards to refer to RLR<br>RLR is 8.700m below primary benchmark B 29 N 16 Kjolsdal III