Frequencies for first 10,000 rows of mager variable in natl2007 dataset :

   Mother's |
Single Year |
 of Age U;R |      Freq.     Percent        Cum.
------------+-----------------------------------
         13 |          2        0.02        0.02
         14 |          2        0.02        0.04
         15 |         25        0.25        0.29
         16 |         64        0.64        0.93
         17 |        154        1.54        2.47
         18 |        277        2.77        5.24
         19 |        481        4.81       10.05
         20 |        488        4.88       14.93
         21 |        573        5.73       20.66
         22 |        632        6.32       26.98
         23 |        641        6.41       33.39
         24 |        695        6.95       40.34
         25 |        638        6.38       46.72
         26 |        613        6.13       52.85
         27 |        605        6.05       58.90
         28 |        517        5.17       64.07
         29 |        507        5.07       69.14
         30 |        455        4.55       73.69
         31 |        431        4.31       78.00
         32 |        365        3.65       81.65
         33 |        322        3.22       84.87
         34 |        308        3.08       87.95
         35 |        283        2.83       90.78
         36 |        224        2.24       93.02
         37 |        178        1.78       94.80
         38 |        146        1.46       96.26
         39 |        112        1.12       97.38
         40 |         93        0.93       98.31
         41 |         60        0.60       98.91
         42 |         46        0.46       99.37
         43 |         27        0.27       99.64
         44 |         13        0.13       99.77
         45 |         12        0.12       99.89
         46 |          4        0.04       99.93
         47 |          4        0.04       99.97
         50 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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