Frequencies for first 10,000 rows of proc3 variable in nhamcsed1993 dataset :

      other |
  procedure |
     #3 - 4 |
      digit |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,993       99.93       99.93
       3404 |          1        0.01       99.94
       3893 |          1        0.01       99.95
       7534 |          1        0.01       99.96
       8939 |          2        0.02       99.98
       9142 |          1        0.01       99.99
       9999 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 28 Mar 2016