| No.of Years | Observations | Observers |
|---|---|---|
| 1981 - 2024 (22) | 394 | 2 |
| Year | Observations | Observers |
|---|---|---|
| 1981 | 1 | 1 |
| 1988 | 1 | 1 |
| 1989 | 1 | 1 |
| 2000 | 1 | 1 |
| 2003 | 1 | 1 |
| 2004 | 1 | 1 |
| 2006 | 3 | 1 |
| 2008 | 4 | 1 |
| 2011 | 11 | 2 |
| 2012 | 6 | 1 |
| 2013 | 11 | 1 |
| 2014 | 16 | 1 |
| 2015 | 8 | 1 |
| 2016 | 17 | 1 |
| 2017 | 23 | 1 |
| 2018 | 19 | 1 |
| 2019 | 27 | 1 |
| 2020 | 29 | 1 |
| 2021 | 46 | 1 |
| 2022 | 52 | 1 |
| 2023 | 89 | 1 |
| 2024 | 27 | 1 |