Frequencies for first 10,000 rows of mage12 variable in natl1992 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         57        0.57        0.57
          3 |         95        0.95        1.52
          4 |        196        1.96        3.48
          5 |        310        3.10        6.58
          6 |        475        4.75       11.33
          7 |        616        6.16       17.49
          8 |      3,102       31.02       48.51
          9 |      2,799       27.99       76.50
         10 |      1,713       17.13       93.63
         11 |        558        5.58       99.21
         12 |         77        0.77       99.98
         13 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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