Frequencies for first 10,000 rows of nseiz variable in linkco1991us_num dataset :

   Seizures |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         52        0.52        0.52
          2 |      8,806       88.06       88.58
          9 |      1,142       11.42      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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