| Time Period | Minimum | 25th Percentile | Median | Average | 75th Percentile | Maximum | Standard Deviation |
|---|---|---|---|---|---|---|---|
| 2004-2008 | 0.77 | 0.97 | 1.04 | 1.04 | 1.10 | 1.37 | 0.09 |
| 2009-2013 | 0.79 | 0.97 | 1.03 | 1.03 | 1.08 | 1.32 | 0.08 |
| 2014-2018 | 0.86 | 0.98 | 1.02 | 1.02 | 1.06 | 1.34 | 0.06 |
| Total | 0.77 | 0.97 | 1.03 | 1.03 | 1.08 | 1.37 | 0.08 |