Frequencies for first 10,000 rows of prov1770 variable in pos1993 dataset :

      renal |
 transplant |
center code |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,937       99.37       99.37
          A |         61        0.61       99.98
          B |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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