Table 1. Prevalence for the current subset excluding Qinghai Lake area (see text).

Subset	c/n	Prev%	Subset	c/n	Prev%	Subset	c/n	Prev%
Full data	577/15614	3.70
		(3.41, 4.01)
Male	250/7839	3.19	Female	327/7764	4.21
		(2.82, 3.61)			(3.78, 4.69)
Han	9/545	1.65	Tibetan	568/15069	3.77
		(0.8, 3.23)			(3.47, 4.09)
Farmer	8/1190	0.07	Semi-herdsmen	8/539	1.48	Student and children	62/3397	1.82
		(0.03, 1.38)			(0.69, 3.02)			(1.41, 2.35)
Employee	27/1136	2.38	Other	56/1363	4.10	Herd people	415/7978	5.20
		(1.60, 3.49)			(3.15, 5.34)			(4.73, 5.72)

c/n indicates the number of AE cases in a subsample of size n; 95 percent confidence interval between parentheses.