Table 3.

Descriptive statistics about influenza zones for each season.

Season	Land Area (106 km2)	Number of Core-Based Statistical Areas in Influenza Zone					Mean Lag (σ)
Influenza Zone		Low Severitya	Moderate Severitya	High Severitya	Very High Severitya	Total
2010–2011
1	0.93	104	0	0	0	104	−0.43 (0.94)
2	1.88	55	0	0	0	55	−0.38 (0.99)
3	0.41	50	0	0	0	50	−3.82 (0.90)
4	3.51	0	175	0	0	175	−0.23 (0.95)
5	0.59	41	0	0	0	41	2.80 (1.12)
6	0.33	25	1	0	0	26	2.23 (0.81)
7	0.99	0	46	8	2	56	2.96 (1.11)
8	0.38	0	55	0	0	55	−3.94 (0.85)
9	0.12	0	0	15	2	17	−2.65 (2.00)
2011–2012
1	5.37	352	17	1	0	369	0.14 (0.78)
2	2.37	120	0	0	0	120	−3.22 (1.29)
3	1.41	0	69	17	3	89	−0.45 (1.78)
2012–2013
1	2.35	0	0	191	13	204	−0.57 (1.38)
2	1.54	1	62	19	2	84	2.70 (1.17)
3	4.66	4	208	0	0	212	−0.01 (0.74)
4	0.60	0	79	0	0	79	−2.91 (1.06)
2013–2014
1	5.79	3	431	24	2	460	−0.16 (1.82)
2	3.36	119	0	0	0	119	0.21 (1.82)
2014–2015
1	8.12	0	51	395	21	467	−0.52 (1.72)
2	1.03	0	0	0	112	112	−0.62 (0.85)
2015–2016
1	6.58	0	347	27	4	378	−0.18 (1.51)
2	2.58	201	0	0	0	201	0.03 (1.08)

^aSeasonal severity categorized using the Moving Epidemic Method (Vega et al., 2013).