Frequencies for first 10,000 rows of proc9 variable in namcs2012 dataset :

   Write-in |
  procedure |
       code |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |     10,000      100.00      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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