Frequencies for first 10,000 rows of ab_aven6 variable in natlterr2007 dataset :

   Assisted |
Ventilation |
 >6 hrs RFP |
629=f_ab_ve |
      nt6 R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      6,163       61.63       61.63
          N |      3,737       37.37       99.00
          U |          1        0.01       99.01
          Y |         99        0.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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