| Year | Value (SE) |
|---|---|
| 2009 | 0.8850 (0.0423) |
| 2010 | 1.1920 (0.1252) |
| 2011 | 0.9550 (0.0266) |
| 2012 | 0.9640 (0.0322) |
| 2013 | 1.1190 (0.1355) |
| 2014 | 1.0190 (0.0751) |
| 2015 | 1.2450 (0.3299) |
| 2016 | 0.9120 (0.0624) |
| 2017 | 0.8660 (0.0654) |
| 2018 | 0.9500 (0.0584) |
| 2019 | 1.0160 (0.0292) |
| 2020 | 1.2020 (0.3343) |
| 2021 | 0.3730 (0.1509) |
| 2022 | 0.7070 (0.1424) |
