Frequencies for first 10,000 rows of isllb8 variable in natl1978 dataset :

   Interval |
 since last |
 live birth |
   Recode 8 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,266       42.66       42.66
          1 |         94        0.94       43.60
          2 |         85        0.85       44.45
          3 |      1,254       12.54       56.99
          4 |      1,128       11.28       68.27
          5 |        925        9.25       77.52
          6 |      1,082       10.82       88.34
          7 |      1,078       10.78       99.12
          8 |         88        0.88      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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