Frequencies for first 10,000 rows of amb2 variable in namcs1995 dataset :

 ambulatory |
   surgical |
proc #2 - 4 |
        dgt |      Freq.     Percent        Cum.
------------+-----------------------------------
       0000 |      9,987       99.87       99.87
       4292 |          1        0.01       99.88
       4911 |          1        0.01       99.89
       6816 |          1        0.01       99.90
       7021 |          1        0.01       99.91
       7024 |          2        0.02       99.93
       9354 |          1        0.01       99.94
       9357 |          4        0.04       99.98
       9359 |          1        0.01       99.99
       9999 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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