Add 2.030m to data values 1935-1977 to refer to RLR<br>Add 7.140m to data values 1978-1983 to refer to RLR<br>Add 2.000m to data values for 1983 to refer to RLR<br>Add 7.140m to data values 1983-1984 to refer to RLR<br>Add 2.000m to data values for 1984 to refer to RLR<br>Add 7.140m to data values 1984-1987 to refer to RLR<br>Add 2.000m to data values 1988 onwards to refer to RLR<br>RLR is 45.908m below primary benchmark BM 4 052 13 1321