| Year | Spring | Summer | Autumn | Winter | Year |
| 2020 | 0.0 | 0.0 | 0.0 | ||
| 2019 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| 2018 | 14.0 | 0.0 | 0.0 | 2.0 | 16.0 |
| 2017 | 0.0 | 0.0 | 0.0 | 14.0 | 14.0 |
| 2016 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| 2015 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| 2014 | 0.0 | 0.0 | 0.0 | 2.0 | 2.0 |
| 2013 | 0.5 | 0.0 | 0.0 | 0.0 | 0.5 |
| 2012 | 0.0 | 0.0 | 0.0 | 4.0 | 4.0 |
| 2011 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| 2010 | 0.0 | 0.0 | 11.0 | 2.5 | 13.5 |
| 2009 | 8.5 | 8.5 |
| Year | Spring | Summer | Autumn | Winter | Year |
| Average | 1.3 | 0.0 | 1.1 | 2.8 | 4.9 |
| Max | 14.0 | 0.0 | 11.0 | 14.0 | 14.0 |
| Min | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
