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Monthly mean North-South sunspot numbers

Monthly mean hemispheric sunspot numbers:

Time range: 1/1992 - 05/2015

Data description: 
Monthly mean North/South sunspot numbers obtained by taking a simple arithmetic mean of the daily North/South sunspot numbers over all days of each calendar month. Each sunspot group is counted in one of the hemispheres based on its heliographic latitude. NB: Hemispheric numbers are always normalized to the corresponding total monthly mean sunspot number (cf. file monthssn.dat)

The 13-month smoothed monthly sunspot numbers are derived by a "tapered-boxcar" running mean of monthly hemispheric sunspot numbers over 13 months centered on the corresponding month (Smoothing function: equal weights = 1, except for first and last elements (-6 and +6 months) = 0.5, Normalization by 1/12 factor). This is the same smoothing as the standard smoothing applied to the total monthly sunspot numbers. There are no smoothed values for the first 6 months and last 6 months of the file. 

Filename: monssnns.dat
Format: plain ASCII text

Column 1: Gregorian calendar date
Column 2: Date in fraction of year for the middle of the corresponding month (~ day 15)
Column 3: North monthly mean sunspot number.
Column 4: South monthly mean sunspot number.
Column 5: Definitive/provisional marker. A blank indicates that the monthly mean values are definitive. A '*' symbol indicates that the monthly values are still provisional and are subject to a possible revision (Usually the last 3 to 6 months)
Column 6: North monthly smoothed sunspot number.
Column 7: South monthly smoothed sunspot number.
Column 8: Definitive/provisional marker as in column 5 but for the smoothed monthly values.

Line format [character position]:
 - [1-4]   Year
 - [5-6]   Month
 - [8-15]  Decimal date
 - [17-21] North monthly mean sunspot number
 - [23-27] South monthly mean sunspot number
 - [29]    Definitive/provisional indicator for monthly numbers
 - [31-35] North monthly smoothed sunspot number
 - [37-41] South monthly smoothed sunspot number
 - [43]    Definitive/provisional indicator for smoothed monthly numbers