Frequencies for first 10,000 rows of mage12 variable in natl1991 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         38        0.38        0.38
          3 |         80        0.80        1.18
          4 |        235        2.35        3.53
          5 |        362        3.62        7.15
          6 |        512        5.12       12.27
          7 |        633        6.33       18.60
          8 |      3,074       30.74       49.34
          9 |      2,789       27.89       77.23
         10 |      1,676       16.76       93.99
         11 |        525        5.25       99.24
         12 |         74        0.74       99.98
         13 |          2        0.02      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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