Table 3. Distribution of strains of Listeria monocytogenes isolated from human case-patients by serovar, by year.

Characteristic	1999	2000	2001	2002	2003	2004	2005	2006	2007*
No. of strains	240	222	186	202	197	233	212	280	151
Serovar 1/2a, %	27	33	33	22	26	30	24	29	27
Serovar 1/2b, %	20	16	22	18	22	11	17	17	15
Serovar 1/2c, %	5	3	3	4	5	4	3	4	4
Serovar 4b, %	48	48	42	55	47	55	56	50	54
Other serovar, %	<1	0	0	<1	0	0	0	<1	<1

*Through Jun 30.