Frequencies for first 10,000 rows of proc6 variable in namcs2013 dataset :

   Write-in |
  procedure |
       code |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |      9,983       99.83       99.83
       1371 |          3        0.03       99.86
       155- |          1        0.01       99.87
       4024 |          1        0.01       99.88
       8908 |          3        0.03       99.91
       8938 |          2        0.02       99.93
       8959 |          1        0.01       99.94
       9052 |          1        0.01       99.95
       9059 |          1        0.01       99.96
       9132 |          3        0.03       99.99
       9509 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 27 Mar 2017