Frequencies for first 10,000 rows of proc3per variable in namcs1993 dataset :

 service #3 |
  performed |
 or ordered |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,813       98.13       98.13
          1 |         88        0.88       99.01
          2 |         81        0.81       99.82
          3 |         18        0.18      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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