| Harvest Year | Average1 | SD | MIN | MAX |
| 2003 | 0.00 | 0.00 | 0.00 | 0.00 |
| 2004 | 7.05 | 4.56 | 0.04 | 21.21 |
| 2005 | 2.89 | 5.46 | 0.00 | 22.92 |
| 2006 | 0.00 | 0.00 | 0.00 | 0.00 |
| 2007 | 0.004 | 0.00 | 0.00 | 0.19 |