| Year | Value (SE) |
|---|---|
| 2011 | 1.0880 (0.2360) |
| 2012 | 1.0140 (0.1415) |
| 2013 | 0.9660 (0.1673) |
| 2014 | 1.1190 (0.1817) |
| 2015 | 0.7170 (0.1141) |
| 2016 | 0.8420 (0.0667) |
| 2017 | 0.7530 (0.0725) |
| 2018 | 0.9870 (0.1259) |
| 2019 | 0.8470 (0.1164) |
| 2020 | 1.1030 (0.1626) |
| 2021 | 0.8140 (0.2082) |
| 2022 | 0.9690 (0.2444) |
| 2024 | 0.9860 (0.2868) |
