Frequencies for first 10,000 rows of proc1per variable in namcs1994 dataset :

 service #1 |
  performed |
 or ordered |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      7,094       70.94       70.94
          1 |      1,780       17.80       88.74
          2 |        864        8.64       97.38
          3 |        262        2.62      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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