Frequencies for first 10,000 rows of proc1per variable in namcs1993 dataset :

 service #1 |
  performed |
 or ordered |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      6,784       67.84       67.84
          1 |      2,222       22.22       90.06
          2 |        757        7.57       97.63
          3 |        237        2.37      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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