Frequencies for first 10,000 rows of prov2030 variable in pos1992 dataset :

       self |
   dialysis |
certificati |
         on |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      9,890       98.90       98.90
          A |         83        0.83       99.73
          B |         21        0.21       99.94
          C |          1        0.01       99.95
          E |          5        0.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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