Sample 1                   Sample 2
           (n=31)                     (n=31)
         =============               ========
Jan        14                            1
Feb      21, 27                      6, 11, 17, 20
Mar       1, 24                         16

Apr       4, 20, 30                      11, 23
May      22, 22, 29     **              13, 17, 21
Jun      1, 6, 8, 16                    11, 11, 30       **

Jul      15, 15         **              9, 20
Aug      9, 10                          6, 10
Sep      25, 25, 25     ***             1, 16, 18, 18    **

Oct       1, 14, 18, 26                  13, 19, 30
Nov      11, 13, 21                      13, 20, 28             **
Dec       1,  26,                        6, 25, 26              **

For n=31, probability of no shared birthdays = 0.270
For n=62, probability of no shared birthdays = 0.004