Frequencies for first 10,000 rows of lmpday variable in natl1981 dataset :

   Day Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        486        4.86        4.86
          2 |        207        2.07        6.93
          3 |        227        2.27        9.20
          4 |        225        2.25       11.45
          5 |        326        3.26       14.71
          6 |        245        2.45       17.16
          7 |        219        2.19       19.35
          8 |        205        2.05       21.40
          9 |        176        1.76       23.16
         10 |        328        3.28       26.44
         11 |        184        1.84       28.28
         12 |        257        2.57       30.85
         13 |        189        1.89       32.74
         14 |        249        2.49       35.23
         15 |        691        6.91       42.14
         16 |        261        2.61       44.75
         17 |        249        2.49       47.24
         18 |        278        2.78       50.02
         19 |        178        1.78       51.80
         20 |        340        3.40       55.20
         21 |        192        1.92       57.12
         22 |        179        1.79       58.91
         23 |        237        2.37       61.28
         24 |        192        1.92       63.20
         25 |        365        3.65       66.85
         26 |        216        2.16       69.01
         27 |        200        2.00       71.01
         28 |        285        2.85       73.86
         29 |        147        1.47       75.33
         30 |        192        1.92       77.25
         31 |         76        0.76       78.01
         99 |      2,199       21.99      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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