| August 2012 | 2.54 | 0.18 |
| February 2013 | 2.67 | 0.26 |
| August 2013 | 2.73 | 0.33 |
| February 2014 | 3.15 | 0.43 |
| August 2014 | 3.85 | 0.5 |
| February 2015 | 4.2 | 0.68 |
| August 2015 | 4.04 | 0.81 |
| February 2016 | 4.08 | 0.95 |
| August 2016 | 4.13 | 1.12 |
| February 2017 | 4.13 | 1.36 |
| August 2017 | 4.13 | 1.49 |
| February 2018 | 4.13 | 1.65 |
| August 2018 | 4.13 | 1.66 |