concentration   subjects	incidence	time
97	10	0	30
170	10	2	30
200	10	5	30
260	10	7	30
260	10	8	30
350	10	10	30
400	10	10	30
120	10	2	60
160	10	6	60
190	10	6	60
220	10	10	60
220	10	9	60