Many stations on the Gulf coast have large values for September 1961.
Documentation added 2011-07-27
The data was downloded from the NOAA site. Datum information was also extracted. The NOAA Primary Benchmark is now NO 10 1973 4.276 above TGZ.
Documentation added 2014-02-13
Whole dataset was downloaded from NOAA. There were data point revised throughout 1971-1972 and 1977-1995. Adjustments were in the order of 2-3mm. Datum level for Sept. 2011 - Oct. 2012 was also adjusted.