Frequencies for first 10,000 rows of scpwi22d variable in namcs2001 dataset :

      scope |
  procedure |
write-in #2 |
  - 2 digit |      Freq.     Percent        Cum.
------------+-----------------------------------
         00 |      9,975       99.75       99.75
         45 |         23        0.23       99.98
         56 |          1        0.01       99.99
         57 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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