Frequencies for first 10,000 rows of ab_aven1 variable in natlterr2013 dataset :

   Assisted |
Ventilation |
        RFP |
628=f_ab_ve |
       nt R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      1,077       10.77       10.77
          N |      8,460       84.60       95.37
          U |        333        3.33       98.70
          Y |        130        1.30      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015