Add 4.186m to data values for 1961 to refer to RLR (1975).
Add 4.196m to data values 1962-1966 to refer to RLR (1975).
Add 3.669m to data values 1967 onwards to refer to RLR (1975).
RLR (1975) is 11.3m below TGBM SX 4468 5434
