Frequencies for first 10,000 rows of lmpday variable in natl1977 dataset :

   Day Last |
     Normal |
     Menses |
      Began |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |        557        5.57        5.57
          2 |        192        1.92        7.49
          3 |        267        2.67       10.16
          4 |        201        2.01       12.17
          5 |        355        3.55       15.72
          6 |        237        2.37       18.09
          7 |        253        2.53       20.62
          8 |        231        2.31       22.93
          9 |        195        1.95       24.88
         10 |        394        3.94       28.82
         11 |        175        1.75       30.57
         12 |        270        2.70       33.27
         13 |        212        2.12       35.39
         14 |        234        2.34       37.73
         15 |        734        7.34       45.07
         16 |        216        2.16       47.23
         17 |        228        2.28       49.51
         18 |        255        2.55       52.06
         19 |        215        2.15       54.21
         20 |        403        4.03       58.24
         21 |        216        2.16       60.40
         22 |        197        1.97       62.37
         23 |        222        2.22       64.59
         24 |        247        2.47       67.06
         25 |        322        3.22       70.28
         26 |        222        2.22       72.50
         27 |        195        1.95       74.45
         28 |        350        3.50       77.95
         29 |        158        1.58       79.53
         30 |        211        2.11       81.64
         31 |         56        0.56       82.20
         99 |      1,780       17.80      100.00
------------+-----------------------------------
      Total |     10,000      100.00

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