dbz	in/h
	70-75	34-69
	65-70	16-34
	60-65	8-16
	55-60	4-8
	50-55	2-4
	45-50	1-2
	40-45	0.5-1
	35-40	0.2-0.4
	30-35	0.1-0.2
	25-30	0.05-0.1
	20-25	0.03-0.05
	15-20	0.01-0.03
	10-15	0.01
	5-10	<0.01