| Time Period | Minimum | 25th Percentile | Median | Average | 75th Percentile | Maximum | Standard Deviation |
|---|---|---|---|---|---|---|---|
| 2004-2008 | 0.54 | 0.66 | 0.71 | 0.71 | 0.76 | 1.32 | 0.10 |
| 2009-2013 | 0.68 | 0.84 | 0.92 | 0.92 | 0.98 | 1.66 | 0.12 |
| 2014-2018 | 0.87 | 1.10 | 1.19 | 1.19 | 1.27 | 2.17 | 0.16 |
| Total | 0.54 | 0.74 | 0.92 | 0.94 | 1.12 | 2.17 | 0.24 |