Frequencies for first 10,000 rows of isllb8 variable in natl1977 dataset :

   Interval |
 since last |
 live birth |
   Recode 8 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,312       43.12       43.12
          1 |        102        1.02       44.14
          2 |         80        0.80       44.94
          3 |      1,251       12.51       57.45
          4 |      1,152       11.52       68.97
          5 |        900        9.00       77.97
          6 |      1,160       11.60       89.57
          7 |        992        9.92       99.49
          8 |         51        0.51      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 3 Jan 2016