Frequencies for first 10,000 rows of proc7 variable in namcs2015 dataset :

   Write-in |
  procedure |
       code |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |      9,998       99.98       99.98
       5732 |          1        0.01       99.99
       5794 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 25 Oct 2017