Frequencies for first 10,000 rows of prov1770 variable in pos1994 dataset :

      renal |
 transplant |
center code |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,938       99.38       99.38
          A |         60        0.60       99.98
          B |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 17 May 2017