Frequencies for first 10,000 rows of ab_aven6 variable in natl2014 dataset :

   Assisted |
Ventilation |
  > 6 hrs Y |
        Yes |      Freq.     Percent        Cum.
------------+-----------------------------------
          N |      9,678       96.78       96.78
          U |        269        2.69       99.47
          Y |         53        0.53      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 15 Jun 2016