Frequencies for first 10,000 rows of proc63d variable in namcs1993 dataset :

 service #6 |
  procedure |
   code - 3 |
     digits |      Freq.     Percent        Cum.
------------+-----------------------------------
        000 |      9,996       99.96       99.96
        819 |          1        0.01       99.97
        887 |          2        0.02       99.99
        933 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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