Frequencies for first 10,000 rows of isllb17 variable in natl1987 dataset :

   Interval |
 since last |
 live birth |
  Recode 17 |      Freq.     Percent        Cum.
------------+-----------------------------------
          0 |      4,438       44.38       44.38
          1 |        106        1.06       45.44
          2 |         82        0.82       46.26
          4 |        287        2.87       49.13
          5 |        337        3.37       52.50
          7 |        353        3.53       56.03
          8 |        333        3.33       59.36
         10 |        615        6.15       65.51
         11 |        512        5.12       70.63
         12 |        807        8.07       78.70
         13 |        591        5.91       84.61
         14 |        409        4.09       88.70
         16 |        283        2.83       91.53
         17 |        211        2.11       93.64
         18 |        130        1.30       94.94
         19 |        115        1.15       96.09
         20 |        328        3.28       99.37
         21 |         63        0.63      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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