Frequencies for first 10,000 rows of amb2 variable in namcs1998 dataset :

 ambulatory |
       surg |
  procedure |
 #2 - 4 dgt |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,982       99.82       99.82
       1829 |          1        0.01       99.83
       184- |          1        0.01       99.84
       4413 |          1        0.01       99.85
       4825 |          1        0.01       99.86
       5732 |          1        0.01       99.87
       598- |          2        0.02       99.89
       6011 |          1        0.01       99.90
       6712 |          1        0.01       99.91
       8396 |          1        0.01       99.92
       8519 |          1        0.01       99.93
       8601 |          1        0.01       99.94
       8604 |          1        0.01       99.95
       8611 |          1        0.01       99.96
       863- |          2        0.02       99.98
       8659 |          1        0.01       99.99
       9357 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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