Frequencies for first 10,000 rows of scpwi23d variable in namcs2005 dataset :

      scope |
  procedure |
     #2 - 3 |
      digit |      Freq.     Percent        Cum.
------------+-----------------------------------
        000 |      9,990       99.90       99.90
        443 |          1        0.01       99.91
        451 |          4        0.04       99.95
        452 |          4        0.04       99.99
        999 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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