=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-Jun-1991
Helsinki            060/351 RLR(1964) is 9.6m below BM7HB
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 12-Jul-1993
Helsinki            060/351 RLR(1964) is 9.6m below BM7HB
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 24-Sep-2002
A description of the sea level network in Finland can be found
in 'Operational Oceanography: Implementation at the European
and Regional scales.  2002 (pp.129-137)'.
1879-1903 VALUES BASED ON 1 READING PER DAY
1904-1970 VALUES BASED ON 6 READINGS PER DAY
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 03-Jan-2012
Levelling information recently supplied by the Finnish Meteorological Institute
confirms Primary benchmark remains 7HB 4.48m above gauge datum of 1904 onwards. 
Previous datum for 1879-1903 was 1.967m above the present datum.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 31-Jan-2017
Following the 2016 levelling exercise some adjustments have been made to the benchmark reference heights - at Helsinki this was +1mm for BM 7HB. The adjustments are a result of more accurate measuring and calculations using the N2000 height system. The RLR diagram has been re-drawn because of this.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 27-Nov-2019
From 2018 onwards the averages of the Finnish sea level data will be based on 1 min observations. Values are calculated in Finnish normal time (EET).
The data are relative to the reference surface of the Finnish sea level observations and thus the datum is the tide gauge zero.