Frequencies for first 10,000 rows of amb23 variable in namcs1998 dataset :

 ambulatory |
       surg |
  procedure |
 #2 - 3 dgt |      Freq.     Percent        Cum.
------------+-----------------------------------
        000 |      9,982       99.82       99.82
        182 |          1        0.01       99.83
        184 |          1        0.01       99.84
        441 |          1        0.01       99.85
        482 |          1        0.01       99.86
        573 |          1        0.01       99.87
        598 |          2        0.02       99.89
        601 |          1        0.01       99.90
        671 |          1        0.01       99.91
        839 |          1        0.01       99.92
        851 |          1        0.01       99.93
        860 |          2        0.02       99.95
        861 |          1        0.01       99.96
        863 |          2        0.02       99.98
        865 |          1        0.01       99.99
        935 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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