Frequencies for first 10,000 rows of prov1760 variable in pos1993 dataset :

      renal |
   dialysis |
center code |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,888       98.88       98.88
          A |        108        1.08       99.96
          B |          3        0.03       99.99
          C |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 26 Jan 2016