Notes on IMP-8 MERGE files.

-- Each folder contains one year of IMP-8 MERGE files, one day per file. 

-- All data files are gzipped.

-- Text file 000_merge_header_row.txt is one-line header with 425 short
names for each column of a record. Users can append this header to the
top of a record to help identify record elements. Text file 
000_merge_header_col.txt contains the 425 element names in 425 rows.