Table 1.

Participant demographic characteristics

Variable	n (%)
	Male	Female	All
Year level (n = 61,759)
Year 4	5584 (17.7)	5466 (18.0)	11,050 (17.9)
Year 5	5765 (18.3)	5675 (18.7)	11,440 (18.5)
Year 6	5691 (18.1)	5542 (18.3)	11,233 (18.2)
Year 7	5318 (16.9)	5089 (16.8)	10,407 (16.9)
Year 8	4620 (14.7)	4478 (14.8)	9098 (14.7)
Year 9	4494 (14.3)	4037 (13.3)	8531 (13.8)
Total	31,472 (51.0)	30,287 (49.0)	61,759 (100)
SES (n = 56,958)
Low	6530 (22.5)	6483 (23.2)	13,013 (22.8)
Medium	13,409 (46.3)	12,880 (46.0)	26,289 (46.2)
High	9031 (31.2)	8625 (30.8)	17,656 (31)

SES Socioeconomic status