Table 1. Age and gender of invitees, respondents and non-respondents to surveys of DAN AP members (DAN-S) and PADI certified divers (PADI-S) and members (PADI-M); age and gender not known in PADI-S non-respondents; NA = not available; *Australian residents only .

	Age (y)	Gender
	mean (SD)	% (male)
DAN AP Members
Invitees (n = 4,235)	53 (13)	73
Respondents (n = 1,119)*	50 (12)	71
PADI Divers
Invitees (n = 37,000)	31 (10)	62
Respondents (n = 806)*	38 (10)	58
PADI Members
Respondents (n = 2,600)	35 (11)	76
Respondents (n = 350)*	44 (12)	70
Non-Respondents (n = 2,250)	NA	NA