Frequencies for first 10,000 rows of proc63d variable in nhamcsopd2010 dataset :

procedure 6 |
  - 2 digit |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |      9,988       99.88       99.88
        456 |          1        0.01       99.89
        470 |          1        0.01       99.90
        482 |          1        0.01       99.91
        857 |          1        0.01       99.92
        861 |          1        0.01       99.93
        863 |          1        0.01       99.94
        882 |          1        0.01       99.95
        893 |          3        0.03       99.98
        950 |          1        0.01       99.99
        999 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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