Frequencies for first 10,000 rows of ab_seiz variable in natlterr2009 dataset :

   Seizures |
        RFP |
633=f_ab_se |
       iz R |      Freq.     Percent        Cum.
------------+-----------------------------------
            |      2,449       24.49       24.49
          N |      7,537       75.37       99.86
          U |          2        0.02       99.88
          Y |         12        0.12      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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