Period | Mean | Standard Deviation | Minimum | Maximum |
August 1996 to March 2015 | 47.0 | 6.6 | 35.7 | 66.6 |
August 1996 to Feb 2008 | 43.7 | 3.6 | 35.7 | 49.0 |
March 2008 to March 2015 | 52.4 | 6.8 | 42.5 | 66.6 |