Add 5.922m to data values for 1978 to refer to RLR<br>Add 5.860m to data values 1980-1997 to refer to RLR<br>Add 5.734m to data values 1998-2002 to refer to RLR<br>Add 5.924m to data values 2003 onwards to refer to RLR<br>RLR is 9.400m below primary benchmark BM