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Study participants by month and region
| Month | Southeast | Northwest | Interior |
|---|---|---|---|
| April | 23 | 29 | 14 |
| May | 16 | 17 | 11 |
| June | 13 | 17 | 14 |
| July | 13 | 19 | 14 |
| August | 17 | 19 | 17 |
| September | 18 | 18 | 9 |
| October | 15 | 18 | 11 |
| November | 16 | 20 | 12 |
| December | 12 | 19 | 15 |
| January | 16 | 19 | 15 |
| February | 16 | 17 | 16 |
| March | 16 | 15 | 15 |
