Year-over-year Case Group Effect* p-value Jul 08 - Jul 09 -0.43 0.28 Aug 08 - Aug 09 -0.50 0.21 Sep 08 - Sep 09 -0.41 0.32 Oct 08 - Oct 09 -0.50 0.23 Nov 08 - Nov 09 -0.63 0.14 Dec 08 - Dec 09 -0.13 0.76 Jul 08 - Jul 10 -0.65 0.14 Aug 08 - Aug 10 -0.25 0.58 Sep 08 - Sep 10 -0.19 0.67 Oct 08 - Oct 10 -0.38 0.41 Nov 08 - Nov 10 -0.41 0.38 Dec 08 - Dec 10 -0.34 0.47 * A negative case group effect indicates that the case group decreased by a greater amount than the control group for the 1-year period under consideration.

Table 1: Effect of being a case relative to being a control for year-over-year comparisons.