Frequencies for first 10,000 rows of ffbef09 variable in h126f dataset :

 TOTAL # OF |
  VISITS IN |
  FF BEFORE |
       2009 |      Freq.     Percent        Cum.
------------+-----------------------------------
         -9 |        150        1.50        1.50
         -1 |      9,819       98.19       99.69
          0 |         30        0.30       99.99
          1 |          1        0.01      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 27 Feb 2018