Frequencies for first 10,000 rows of scpwi23d variable in namcs2006 dataset :

      scope |
  procedure |
     #2 - 3 |
      digit |      Freq.     Percent        Cum.
------------+-----------------------------------
        000 |      9,981       99.81       99.81
        451 |          7        0.07       99.88
        452 |          2        0.02       99.90
        999 |         10        0.10      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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