Table 1. Syphilis incidence seasonal indices.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Primary syphilis	0.88	0.81	1.06	1.03	1.10	1.08	1.09	1.10	1.01	1.00	0.95	0.86
Secondary syphilis	0.86	0.77	0.98	0.99	1.19	1.25	1.27	1.24	1.04	0.96	0.80	0.65
Tertiary syphilis	0.96	0.82	1.05	1.02	1.14	1.07	1.05	1.06	0.97	1.00	0.97	0.87
Latent syphilis	0.82	0.78	1.06	1.01	1.08	1.06	1.07	1.08	1.03	1.04	1.02	0.96
Congenital syphilis	0.90	0.81	0.97	0.91	0.97	0.96	1.08	1.14	1.08	1.12	1.07	0.98