Frequencies for first 10,000 rows of proc4 variable in namcs2010 dataset :

procedure 4 |
  - 4 digit |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |      9,931       99.31       99.31
       0040 |          1        0.01       99.32
       286- |          1        0.01       99.33
       3721 |          1        0.01       99.34
       5349 |          1        0.01       99.35
       8913 |          1        0.01       99.36
       8938 |         14        0.14       99.50
       8959 |          6        0.06       99.56
       897- |          1        0.01       99.57
       9396 |          4        0.04       99.61
       9509 |         37        0.37       99.98
       9947 |          1        0.01       99.99
       9955 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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