Table 2.

Noise measurements

	Entire study period (1992-2011)				Final 3 years (2009-2011)				Final / entire study period
Location	N meas.	Mean n meas./ year	Mean n employees	Mean n meas./ year per 100 employees	N meas.	Mean n meas./ year	Mean n employees	Mean n meas./ year per 100 employees	Ratio of normalized rates
Total	10,782	539	8,441	6.4	1,499	500	7,158	7.0	1.1
1	2,174	109	1,204	9.0	238	79	1,096	7.2	0.8
2	1,248	62	991	6.3	247	82	781	10.5	1.7
3	2,273	114	1,805	6.3	193	64	1,681	3.8	0.6
4	765	38	777	4.9	554	185	642	28.8	5.9
5	1,273	64	844	7.5	190	63	616	10.3	1.4
6	516	26	593	4.4	80	27	466	5.7	1.3
7	1,888	94	1,804	5.2	171	57	1,562	3.6	0.7
8	645	32	422	7.6	238	79	1,096	7.2	0.9