Frequencies for first 10,000 rows of proc4per variable in namcs1993 dataset :

 service #4 |
  performed |
 or ordered |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,945       99.45       99.45
          1 |         24        0.24       99.69
          2 |         21        0.21       99.90
          3 |         10        0.10      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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