Frequencies for first 10,000 rows of proc42d variable in namcs2009 dataset :

procedure 4 |
  - 2 digit |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |      9,920       99.20       99.20
         04 |          4        0.04       99.24
         81 |          2        0.02       99.26
         89 |         58        0.58       99.84
         90 |          1        0.01       99.85
         93 |          3        0.03       99.88
         94 |          1        0.01       99.89
         95 |          3        0.03       99.92
         96 |          1        0.01       99.93
         99 |          7        0.07      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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