Table 1.

Demographic characteristics of the subjects.

Age	Gender				Total
	Male		Female
	No.	%	No.	%	No.	%
<12 months	134	40.7	114	42.1	248	41.3
12 - <24 months	46	7.7	42	7.0	88	14.7
24 - <36 months	21	3.5	19	3.2	40	6.7
36 - <48 months	25	4.2	19	3.2	44	7.3
48 - <60 months	22	3.7	16	2.7	38	6.3
60 - <180 months	81	24.6	61	22.5	142	23.7
Social class
I	22	6.7	19	7.0	41	6.8
II	58	17.6	41	15.1	99	16.5
III	109	33.4	85	31.4	194	32.3
IV	121	37.1	104	38.4	225	37.5
V	10	3.0	17	6.3	27	4.5
Unknown	9	1.8	5	1.8	14	2.3
Total	329	54.8	271	45.2	600	100