Add 7.0m to all data values June 1993 to June 1998 to refer to RLR (1994)
Add 7.008m to all data values April 1999 to March 2001 to refer to RLR (1994)
Add 6.996m to all data values Nov. and Dec. 2005 to refer to RLR (1994)
Add 7.0m to all data values Jan. 2006 to Dec. 2007 to refer to RLR (1994)
Add 6.996m to all data values Jan. 2008 to May 2010 to refer to RLR (1994)
Add 6.130m to data values Dec. 2010 onwards to refer to RLR (1994)
RLR (1994) is 10.184m below BM POL 13
