Frequencies for first 10,000 rows of proc4per variable in namcs1994 dataset :

 service #4 |
  performed |
 or ordered |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,932       99.32       99.32
          1 |         24        0.24       99.56
          2 |         36        0.36       99.92
          3 |          8        0.08      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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