Table 3. Norovirus GII.4 variants in outbreaks during July 2000 to June 2008.

Observation Period	Jul00 to Jun01	Jul01 to Jun02	Jul02 to Jun03	Jul03 to Jun04	Jun04 to Jul05	Jul05 to Jun06	Jul06 to Jun07	Jul07 to Jun08
Number of norovirus GII outbreaks by sequence	21	3	75	13	158	55	259	93
Number of GII.4 variants outbreaks (%)	18 (85.7)	2 (66.7)	71 (94.7)	10 (76.9)	148 (93.7)	41 (74.5)	252 (97.3)	75 (80.6)
GII.4-1996	18			2
GII.4-2002		2	61	8	5
GII.4-2004					141	18
GII.4-2006a					2	9	62	5
GII.4-2006b						12	189	61
GII.4-2008a								1
GII.4-2008b								4
GII.4-other			10			2	1	4