Frequencies for first 10,000 rows of proc6per variable in namcs1994 dataset :

 service #6 |
  performed |
 or ordered |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      9,994       99.94       99.94
          1 |          2        0.02       99.96
          2 |          4        0.04      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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