Frequencies for first 10,000 rows of proc63d variable in nhamcsopd1993 dataset :

 service #6 |
  procedure |
   code - 3 |
     digits |      Freq.     Percent        Cum.
------------+-----------------------------------
        000 |      9,993       99.93       99.93
        751 |          1        0.01       99.94
        874 |          1        0.01       99.95
        876 |          1        0.01       99.96
        892 |          1        0.01       99.97
        914 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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