 Usage:  freq=frequency(x{,xvars{,outwidth})  
 
 Input:

  x                      n x p matrix, the columns correspond to the 
                         variables. The matrix may be numeric or string. 
                         
  xvars                  optional, p x 1 string vector, variable names. 
                         
  outwidth               optional, integer<71, outwidth for categories, 
                         default=15. 
                         
 Output:

  freq                   string output, containing frequency table(s). 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
