| Year/Participants | Total | |
|---|---|---|
| n | % | |
| 2008 | 5473 | 100 |
| Cancer cases | 9 | 0.16 |
| 2009 | 6893 | 100 |
| Cancer cases | 16 | 0.23 |
| 2010 | 5082 | 100 |
| Cancer cases | 15 | 0.29 |
| 2011 | 12,179 | 100 |
| Cancer cases | 21 | 0.17 |
| 2012 | 33,274 | 100 |
| Cancer cases | 4 | 0.01 |
| Total 2008–2012 | 62,901 | 100 |
| Cancer cases | 65 | 0.10 |