| Month/year of survey | BSE | Pv | Pf | Mixed | TPC | SPR | SFR | Pf % |
| February 1997 | 24 | 0 | 6 | 0 | 6 | 25.0 | 25.0 | 100.0 |
| November 1999 | 341 | 12 | 225 | 6 | 243 | 71.2 | 65.9 | 95.1 |
| April 2007 | 190 | 27 | 59 | 0 | 86 | 45.3 | 31.0 | 68.6 |
| August 2014 | 263 | 14 | 10 | 0 | 24 | 9.12 | 3.80 | 41.7 |
| Total | 818 | 53 | 294 | 6 | 353 | 43.1 | 35.9 | 83.3 |