| Sample | Proportion | Groups | ||||
| 2016 | 0.0240 | A |
|
|
|
|
| 2015 | 0.0283 |
| B |
|
|
|
| 2014 | 0.0327 |
|
| C |
|
|
| 2013 | 0.0334 |
|
|
| D |
|
| 2012 | 0.0372 |
|
|
|
| E |