Frequencies for first 10,000 rows of lmpday variable in natl1976 dataset :

   Day Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        549        5.49        5.49
          2 |        216        2.16        7.65
          3 |        234        2.34        9.99
          4 |        224        2.24       12.23
          5 |        316        3.16       15.39
          6 |        251        2.51       17.90
          7 |        230        2.30       20.20
          8 |        247        2.47       22.67
          9 |        179        1.79       24.46
         10 |        418        4.18       28.64
         11 |        187        1.87       30.51
         12 |        276        2.76       33.27
         13 |        223        2.23       35.50
         14 |        240        2.40       37.90
         15 |        666        6.66       44.56
         16 |        259        2.59       47.15
         17 |        245        2.45       49.60
         18 |        271        2.71       52.31
         19 |        192        1.92       54.23
         20 |        435        4.35       58.58
         21 |        223        2.23       60.81
         22 |        222        2.22       63.03
         23 |        240        2.40       65.43
         24 |        214        2.14       67.57
         25 |        353        3.53       71.10
         26 |        227        2.27       73.37
         27 |        216        2.16       75.53
         28 |        329        3.29       78.82
         29 |        177        1.77       80.59
         30 |        216        2.16       82.75
         31 |         63        0.63       83.38
         99 |      1,662       16.62      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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