Frequencies for first 10,000 rows of othproc4 variable in nhamcsopd2008 dataset :

procedure 4 |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |      9,995       99.95       99.95
       222- |          1        0.01       99.96
       8938 |          1        0.01       99.97
       8959 |          1        0.01       99.98
       9032 |          1        0.01       99.99
       9509 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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