| Time Period | Minimum | 25th Percentile | Median | Average | 75th Percentile | Maximum | Standard Deviation |
|---|---|---|---|---|---|---|---|
| 2004-2008 | 0.53 | 0.70 | 0.76 | 0.79 | 0.83 | 1.71 | 0.13 |
| 2009-2013 | 0.61 | 0.82 | 0.89 | 0.91 | 0.96 | 1.90 | 0.15 |
| 2014-2018 | 0.74 | 0.98 | 1.07 | 1.10 | 1.16 | 2.18 | 0.18 |
| Total | 0.53 | 0.78 | 0.90 | 0.93 | 1.05 | 2.18 | 0.20 |