Frequencies for first 10,000 rows of ab_aven6 variable in natl2017 dataset :

   Assisted |
Ventilation |
  > 6 hrs Y |
        Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,684       96.84       96.84
          U |         72        0.72       97.56
          Y |        244        2.44      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 19 Sep 2018