| Time Period | Minimum | 25th Percentile | Median | Average | 75th Percentile | Maximum | Standard Deviation |
|---|---|---|---|---|---|---|---|
| 2004-2008 | 0.60 | 0.67 | 0.68 | 0.69 | 0.70 | 0.88 | 0.03 |
| 2009-2013 | 0.94 | 1.01 | 1.03 | 1.02 | 1.04 | 1.10 | 0.03 |
| 2014-2018 | 1.12 | 1.26 | 1.30 | 1.29 | 1.33 | 1.43 | 0.05 |
| Total | 0.60 | 0.70 | 1.03 | 1.00 | 1.26 | 1.43 | 0.25 |