Frequencies for first 10,000 rows of totamb variable in namcs2000 dataset :

     total # of ambulatory surgical |
                         procedures |      Freq.     Percent        Cum.
------------------------------------+-----------------------------------
                                  0 |      9,332       93.32       93.32
                                  1 |        289        2.89       96.21
                                  2 |         21        0.21       96.42
All fields blank including None box |        358        3.58      100.00
------------------------------------+-----------------------------------
                              Total |     10,000      100.00

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