Frequencies for first 10,000 rows of mage12 variable in natl1973 dataset :

     Age of |
     Mother |
  recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |         78        0.78        0.78
          3 |        209        2.09        2.87
          4 |        383        3.83        6.70
          5 |        561        5.61       12.31
          6 |        726        7.26       19.57
          7 |        824        8.24       27.81
          8 |      3,471       34.71       62.52
          9 |      2,316       23.16       85.68
         10 |        925        9.25       94.93
         11 |        396        3.96       98.89
         12 |        106        1.06       99.95
         13 |          5        0.05      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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