This format is intended to be easily readable for both humans and computer programs and have some resemblance to the regular mail distribution.
Since many observatories are interested mainly in the international quietest and most disturbed days, beginning August 1996 three extra lines have been added to the end of the table containing these values in an easy to read form. The extra lines are included in the complete monthly tables only.
The geomagnetic indices in the kpyymm.tab files are supplied in the following format:
Line 1: This line contains the monthly mean values for Ap and Cp:
Line 2: Empty
Line 3: This line contains the ordered most quiet days:
Line 4: This line contains the ordered most disturbed days: