Add 7.035m to data values 1977-1978 to refer to RLR<br>Add 1.895m to data values 1978-1979 to refer to RLR<br>Add 7.035m to data values 1979-1983 to refer to RLR<br>Add 1.895m to data values for 1983 to refer to RLR<br>Add 7.035m to data values 1983-1984 to refer to RLR<br>Add 1.895m to data values for 1985 to refer to RLR<br>Add 7.035m to data values for 1985 to refer to RLR<br>Add 1.895m to data values for 1985 to refer to RLR<br>Add 7.035m to data values for 1985 to refer to RLR<br>Add 1.895m to data values for 1986 to refer to RLR<br>Add 7.035m to data values 1986-1989 to refer to RLR<br>Add 1.895m to data values 1990 onwards to refer to RLR<br>RLR is 13.700m below primary benchmark BM no. 4 065 33 1191 (HN76)