Frequencies for first 10,000 rows of ab_aven1 variable in natlterr2011 dataset :

   Assisted |
Ventilation |
        RFP |
628=f_ab_ve |
       nt R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      2,536       25.36       25.36
          N |      6,246       62.46       87.82
          U |      1,094       10.94       98.76
          Y |        124        1.24      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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